CLRC 2018 - 19th Coherent Laser Radar Conference

19th Coherent Laser Radar Conference

DATE:18th-21st June, 2018

VENUE:Okinawa, Japan

Program

  • Monday
  • Tuesday
  • Tuesday (Poster session)
  • Wednesday
  • Thursday

Day 1

7:50 - 9:00 Reception and Registration
8:45 - 9:00 Welcome and Opening Remarks
9:00 - 9:40

Keynote speech

Chairman : Shoken Ishii (NICT)

Coherent Laser Radar - from global wind sensing to the detection of GravitationalWaves

Robert L. Byer (Stanford University)

Coherent Laser Radar - from global wind sensing to the detection of GravitationalWaves

Coherent Laser Radar based on solid state lasers was motivated by the need for efficient, highly coherent lasers on orbit for observation of global winds. The challenge led to the invention of the monolithic non-planar ring oscillator (NPRO) in Nd:YAG. The Laser Interferometer GravitationalWave Observatory (LIGO) selected Nd:YAG lasers to power the 4km-scale interferometers.
Today, advanced LIGO uses the NPRO and a 180W Nd:YAG power amplifier. The detection of gravitational waves opened a new era of multi-messenger astronomy with observations in gravitational waves (audio frequency region) and electromagnetic waves. The principles of coherent laser radar are now powering not only engineering applications in transportation and communications but also fundamental science and astrophysics applications at unprecedented resolutions and sensitivities.

9:40 - 10:50

Space-based lidars I

Chairman : Stephan Rahm (DLR)

9:40 - 10:05 Invited

ESA wind lidar mission Aeolus

Alain M. Dabas (Meteo-France), Thomas Flament (Meteo-France), Frank de Bruin (European Space Agency), Anne Straume I, Thomas Kanitz I, Oliver Reitebuch (DLR), Uwe Marksteiner (DLR), Dorit Huber (Dorit), Lars Isaksen (ECMWF), Micheal Rennie I, Ad Stoffelen I, Gert-Jan Marseille (KNMI), Jos De Kloe I, Olivier Lecrenier (Airbus Defense and Space), Jeremie Lochard (Airbus Defense and Space), and Phil Mcgoldrick (Airbus Defense and Space)

ESA wind lidar mission Aeolus

Due to be launched in a few months, ESA Aeolus mission will be the first Doppler wind lidar in space. Implementing a dual Mie/Rayleigh receiver, Aeolus will measure vertical profiles of one wind component from the ground up to the lower stratosphere. The observations will be delivered in near-real time so they can be assimilated by numerical weather prediction systems. Although not optimized for this purpose, Aeolus will be also the first high-spectral resolution lidar in space and as such provide information of clouds and vertical profiles of aerosol optical properties to be assimilated by air quality prediction systems. The status of the mission a few months before launch will be presented with the results of the numerous qualifying tests conducted recently. The measurement principles and the available products will be recalled with their expected horizontal and vertical resolutions and accuracy.

10:05 - 10:30 Invited

Results from recent airborne campaigns aiming at the preparation of ESA's

Benjamin Witschas (DLR, Institute of Atmospheric Physics, 82234 Oberpfafenhofen), Christian Lemmerz (DLR, Institute of Atmospheric Physics, 82234 Oberpfafenhofen), Oliver Lux (DLR, Institute of Atmospheric Physics, 82234 Oberpfafenhofen), Uwe Marksteiner (DLR, Institute of Atmospheric Physics, 82234 Oberpfafenhofen), Stephan Rahm (DLR, Institute of Atmospheric Physics, 82234 Oberpfafenhofen), Oliver Reitebuch (DLR, Institute of Atmospheric Physics, 82234 Oberpfafenhofen), Andreas Schafler (DLR, Institute of Atmospheric Physics, 82234 Oberpfafenhofen), and Fabian Weiler (DLR, Institute of Atmospheric Physics, 82234 Oberpfafenhofen)

Results from recent airborne campaigns aiming at the preparation of ESA's

Almost 20 years after its selection as an Earth Explorer Core Mission of ESA's Living Planet Program, Aeolus is ready to be launched in 2018. Aeolus will carry the first wind lidar instrument in space, ALADIN (Atmospheric Laser Doppler Instrument), aiming at the measurement of vertical wind profiles globally from ground to 25 km. To validate ALADIN's measurement principle and calibration routines, DLR has developed an airborne Cal/Val payload based on the direct detection wind lidar system A2D (355 nm), and a coherent detection wind lidar system (2 µm) which was deployed in several field campaigns within the last years. From September to October 2016, as part of the international campaign NAWDEX (North Atlantic Waveguide and Downstream Impact Experiment), several flights have been performed from the airport of Keflavik, Iceland. In this paper, an overview of results obtained during NAWDEX and their conclusion Aeolus Mission will be discussed.

10:30 - 10:50

Evaluation of potential impacts of future Japan’s space-based Doppler Wind Lidar (DWL) on polar- and tropical-orbiting satellites

Kozo Okamoto (JMA/MRI/NICT), Toshiyuki Ishibashi (JMA/MRI), Shoken Ishii (NICT), Philippe Baron (NICT), Kyoka Gamo (FUJITSU FIP Corporation), Taichu Tanaka (JMA/MRI), Koji Yamashita (Meteorological Satellite Center of JMA), and Takuji Kubota (JAXA)

Evaluation of potential impacts of future Japan’s space-based Doppler Wind Lidar (DWL) on polar- and tropical-orbiting satellites

We have been investigating the feasibility of coherent DWLs based on a sensitivity observation system simulation experiment (OSSE). The pseudo-truth atmospheric field is generated from the Sensitivity Observing System Experiment (SOSE) approach. Hourly aerosols are produced to simulate DWL by a global aerosol chemical transport model developed by MRI in which wind field is nudged with pseudo-truth. Simulated line-of-sight wind speeds are assimilated by using the four-dimensional variational (4D-Var) scheme of the operational global data assimilation system at JMA. We evaluated potential impacts of DWLs onboard polar and low-inclination orbiting satellites in January and August in 2010. This study showed new findings of seasonal dependency of impacts and importance of quality control and observation error setting. For example, we found positive impacts of DWLs on either satellites and greater impact in January. Furthermore, DWL assimilation could cause negative impacts without appropriate quality control procedures and observation errors settings.

10:50 - 11:10 Coffee Break
11:10 - 12:20

Lasers & Devices I

Chairman : Upendra N. Singh (NASA)

11:10 - 11:35 Invited

DAWN in CPEX campaign and Space pathfinder coherent wind lidar development at LaRC

Jirong Yu (NASA Langley Resear Center), Michael J. Kavaya (NASA Langley Resear Center), Larry B. Petway (NASA Langley Resear Center), Songsheng Chen (NASA Langley Resear Center), John E. Marketon (NASA Langley Resear Center), Sammy Henderson, and David Emmitt

DAWN in CPEX campaign and Space pathfinder coherent wind lidar development at LaRC

Recently, the NASA Langley high power Doppler AerosolWiNd (DAWN) instrument participated in NASA 2017 CPEX campaign, a field experiment to study Convective Processes in the Tropics. It provides previously unavailable high resolution and high sensitivity 3D wind profiles with a vertical resolution of 50m as well as LOS wind measurements every 25-50 m horizontally over the open ocean. Currently, NASA Langley is developing a space pathfinder coherent wind lidar instrument with a lidar performance meeting the space wind lidar figure of merit requirements. It operates at 200 pulse repletion range, 55mJ pulse energy, 150-200ns pulse width and with beam quality M2 value better than 1.1. This instrument is suitable for International space station platform to measure global 3D winds. In this paper, we will describe the DAWNinstrument sensitivity improvements and its performance during the CPEX campaign, and the space pathfinder coherent wind lidar instrument development progresses.

11:35 - 12:00 Invited

High-average-power, conductively cooled Tm,Ho:YLF laser for Doppler wind lidar

Atsushi Sato (Tohoku Institute of Technology / National Institute of Information and Communications Technology), Makoto Aoki (National Institute of Information and Communications Technology), Shoken Ishii (National Institute of Information and Communications Technology), Kohei Mizutani (National Institute of Information and Communications Technology), Satoshi Ochiai (National Institute of Information and Communications Technology), and Minoru Kubota (National Institute of Information and Communications Technology)

High-average-power, conductively cooled Tm,Ho:YLF laser for Doppler wind lidar

Conductively cooled Tm,Ho:YLF lasers are one of the most promising laser sources for a spaceborne Doppler wind lidar. In this study, high-average-power operation of a conductively-cooled Tm,Ho:YLF laser was demonstrated at -80°C. At a pulse repetition frequency of 70 Hz, a Qswitched pulse energy of 104 mJ was obtained. This corresponds to an average output power of 7.28 W, which is the highest average power for a 100-mJ-class Q-switched Tm,Ho:YLF laser oscillator with conductive cooling. The maximum output energy reached 125 mJ at 50 Hz. Based on these results, an optical design of a master oscillator and power amplifier system operating at-40°C was investigated to reduce the power consumption of the laser transmitter.

12:00 - 12:20

9-mJ laser amplifier at 1540 nm for a coherent lidar system with 250 Hz repetition

Kenichi Hirosawa (Mitsubishi Electric Corporation), Takeshi Sakimura (Mitsubishi Electric Corporation), Narito Samejima (Mitsubishi Electric Corporation), Takayuki Yanagisawa (Mitsubishi Electric Corporation), and Shumpei Kameyama (Mitsubishi Electric Corporation)

9-mJ laser amplifier at 1540 nm for a coherent lidar system with 250 Hz repetition

We have developed a coherent lidar system for wind detection from 1998, which uses high energy laser sources at 1550 nm or other C-band wavelength. In the present system, the laser source consists of a narrow-bandwidth laser diode, an AO modulator, a fiber amplifier and a planar waveguide amplifier. To amplify eye-safe C-band wavelength, the planar waveguide amplifier has Er, Yb co-doped glass as a core of waveguide. The planar waveguide suppress nonlinear effects such as stimulated Brillouin scattering because it accepts larger beam width than single mode optical fibers. Therefore, higher output energy can be achieved than conventional fiber amplifiers. In this paper, we modified the structure of the planar waveguide, and achieved 9 mJ with 250 Hz repetition rate. The power performance with various repetition rates will be presented.

12:20 - 13:40 Lunch Break
13:40 - 15:10

Photonic integrated-circuit lidars

Chairman : Toshiyuki Ando (Mitsubishi Electric Corp.)

13:40 - 14:05 Invited

Photonic Integrated Circuit FMCW Lidar On A Chip

Paul J. Suni (Lockheed Martin Coherent Technologies), James R. Colosimo (Lockheed Martin Coherent Technologies), John Bowers (University of California at Santa Barbara), Larry Coldren (University of California at Santa Barbara), S.j. B. Yoo (University of California at Davis), and Jonathan Klamkin (University of California at Santa Barbara)

Photonic Integrated Circuit FMCW Lidar On A Chip

Photonic integrated circuits (PICs) enable construction of complex optical systems at a miniaturized scale not possible with bulk elements. All active and passive components required to fabricate chip-scale coherent lidar systems have been demonstrated and system demonstrations are currently underway. In this paper we describe our efforts to demonstrate a chip-scale frequency modulated continuous-wave (FMCW) lidar. This system incorporates wavelength tuning and optical phased array (OPA) operation to enable 2D non-mechanical beam steering. We further discuss approaches aimed at scaling aperture dimensions from mm scales to 10 cm scales, as well as work to reduce phased array pitches to sub-wavelength dimensions in order to minimize far-field sidelobes. These efforts include development of micron-sized mirror arrays to enable coupling between optical layers and demonstration of wafer-scale routing of light at high efficiency.

14:05 - 14:30 Invited

Advantages of 3D Imaging Coherent Lidar for Autonomous Driving Applications

Stephen C. Crouch (Blackmore Sensors and Analytics Inc.)

Advantages of 3D Imaging Coherent Lidar for Autonomous Driving Applications

Blackmore has developed the first real-time, 3D imaging lidar product based on frequency modulation and coherent detection for autonomous driving applications. Units began shipping to automotive customers in late 2017. The technology provides long range performance (>300m), impressive point throughput (300k to 1.2M points per second per scanned beam), total interference immunity, and a unique ability to measure radial velocity on each 3D data point. In addition, continuous wave transmission is an ideal fit for integrated photonics and solid-state scanning solutions such as optical phased arrays. These advantages highlight an incredible market opportunity for coherent lidar systems in automotive and other consumer applications where direct detection lidar fails to meet system requirements. Technology building blocks in high-throughput processing, integrated photonics and optical phased array technology, all under development at Blackmore, will be presented in addition to exciting mobile, geo-registered 3D point cloud data results.

14:30 - 14:50

Coherent Lidar for 3D-imaging through obscurants

Aude Martin (Thales Research and Technology, Palaiseau, France), Jerome Bourderionnet (Thales Research and Technology, Palaiseau, France), Luc Leviandier (Thales Research and Technology, Palaiseau, France), John F. Parsons (Thales Ltd, Reading, Berkshire, UK), Mark Silver (Thales Ltd, Glasgow, UK), and Patrick Feneyrou (Thales Research and Technology, Palaiseau, France)

Coherent Lidar for 3D-imaging through obscurants

In the context of unmanned vehicles, eye-safe LiDARs able to measure simultaneously range and speed with no or few moving parts even in degraded visual environments, are required. The ability of frequency modulated continuous wave coherent LiDAR at 1.55 µm to differentiate hard target from diffuse ones like clouds or dust is used here to demonstrate 3D-imaging of hard targets through obscurants. We will also present detection experiments, where we measure range and speed of a target using a compact FMCW LiDAR based on silicon photonics. It consists of 8 transmit and 8 receive switchable channels and of an additional channel for waveform calibration. The photonic integrated circuit, without any moving part, allows emission and detection in 8 different collimated directions spread over the desired angle.

14:50 - 15:10

An optical scanner on silicon photonics integrated circuit for LIDAR application

Daisuke Inoue (Toyota Central R&D labs. Inc.), Tadashi Ichikawa (Toyota Central R&D labs. Inc.), Akari Kawasaki (Toyota Central R&D labs. Inc.), and Tatsuya Yamashita (Toyota Central R&D labs. Inc.)

An optical scanner on silicon photonics integrated circuit for LIDAR application

Recently technologies for self-driving of cars attract rising attention. Environment monitoring sensors are important technology for automated cruising. We consider that imaging LIDAR is one of promising sensor for self-driving technology. A lot of electronic components are densely packed in automobile, so compact devices are preferred for automotive application. We are developing a LIDAR integrated on photonic integrated circuit. We demonstrated and fabricated an optical scanner based on beam switching method. Device is consisted of imaging lens and photonics integrated circuit. Our scanner is movement free and suitable for mass-production.

15:10 - 15:30 Coffee Break
15:30 - 16:30

Measurement, simulation, modeling, and signal processing I

Chairman : Songhua Wu (Ocean University of China)

15:30 - 15:50

Synergetic observations of downbursts using a Doppler lidar and radars in Okinawa, Japan

Hironori Iwai (National Institute of Information and Communications Technology), Makoto Aoki (National Institute of Information and Communications Technology), Shinsuke Satoh (National Institute of Information and Communications Technology), Takeharu Koketsu (National Institute of Information and Communications Technology), Hiroyuki Yamada (University of the Ryukyus), Tadayasu Ohigashi (Kyoto University), Taro Shinoda (Nagoya University), and Kazuhisa Tsuboki (Nagoya University)

Synergetic observations of downbursts using a Doppler lidar and radars in Okinawa, Japan

On 28 July 2016, an isolated convective storm produced two downbursts within about 10 km north from a Doppler lidar at NICT’s Okinawa Electromagnetic Center in Okinawa, Japan. Concentric circular patterns of the Doppler velocity, spectral width, and carrier-to-noise ratio were detected near the sea surface in the 0°-elevation sector plane position indicator scans of the Doppler lidar. An X-band phased array weather radar (PAWR) detected the first echo approximately 13 min prior to the near-surface divergent signature of the downbursts. The PAWR provided 30-sec volumetric data of the storm and observed rapid evolution of reflectivity cores with >65-dBZ radar reflectivity. The cores descended rapidly toward the sea surface. The associated differential reflectivity minimum was observed by an X-band polarimetric radar. In this paper, we show that the synergetic use of different remote sensing instruments is important for better understanding the physical processes of downburst evolution.

15:50 - 16:10

Estimating Atmospheric Boundary Layer Height using Large-scale Coherent Doppler

Kohin Hirano (National Research Institute for Earth Science and Disaster Resilience), Shin-ichi Suzuki (National Research Institute for Earth Science and Disaster Resilience), Takeshi Maesaka (National Research Institute for Earth Science and Disaster Resilience), and S. B. Grimmond (University of Reading)

Estimating Atmospheric Boundary Layer Height using Large-scale Coherent Doppler

The atmospheric boundary layer is important because it affects exchanges of momentum, heat, moisture, and aerosol between the surface and the free atmosphere above. Several methods have been proposed to estimate boundary layer height (BLH) using various remote sensing instruments. As part of the National Institute for Earth Science and Disaster Resilience (NIED, Japan) efforts to improve detection of storm clouds forming and weather forecasting through data assimilation, it has established a ground base remote sensing network in great Tokyo area since 2014 FY. The network includes 3 Large-scale Coherent Doppler Lidar (LDL) manufactured by Mitsubishi Electric, which have high power laser amplifier using Er, Yb:glass planer waveguide and output Doppler velocity, Doppler velocity width and signal-to-noise rate (SNR). This paper reports the estimation of BLH using these lidars and compares the results with subjective methods.

16:10 - 16:30

Aerosol profile measurement by a high-spectral-resolution lidar with a scanning interferometer

Yoshitaka Jin (National Institute for Environmental Studies), Nobuo Sugimoto (National Institute for Environmental Studies), Tomoaki Nishizawa (National Institute for Environmental Studies), and Hajime Okamoto (Research Institute for Applied Mechanics, Kyushu University)

Aerosol profile measurement by a high-spectral-resolution lidar with a scanning interferometer

A simple high-spectral-resolution lidar (HSRL) is developed for continuous observation of aerosol profile. The second harmonic of an injection-seeding Nd:YAG laser is used for the light source. A scanning interferometer is used to separate the Rayleigh and Mie backscattering components. The interferometer is periodically scanned in the span of one fringe. Lidar signals at the minimum and maximum Mie scattering transmission are obtained. Rayleigh scattering signals are derived by subtracting the bias (cross-talk) component from the lidar signals at the minimum Mie scattering transmission, and the aerosol extinction coefficient is retrieved. The interferometer transmittance and the fringe position are calibrated with the reference signals taken from a portion of the transmitted laser beam. The method is originally developed for an HSRL with a multimode laser, but the measurement sensitivity is higher when using a single-mode laser.

Day 2

8:00 - 9:00 Reception and Registration
9:00 - 10:05

Measurement, simulation, modeling, and signal processing II

Chairman : Nobuo Sugimoto (National Institute for Environmental Studies)

9:00 - 9:25 Invited

Vertical Wind Patterns in the NYC Built Environment: Wind LIDAR Observations of Dispersion and Downburst Behavior

Mark J. Campmier (Environmental Engineering Program, CUNY City College of New York), Aris Fernandez (NOAA-CREST Center, CUNY City College of New York / Electrical Engineering Department, CUNY City College of New York), Yonghua Wu (NOAA-CREST Center, CUNY City College of New York), Fred Moshary (Environmental Engineering Program, CUNY City College of New York / NOAA-CREST Center, CUNY City College of New York / Electrical Engineering Department, CUNY City College of New York), and Mark Arend (NOAA-CREST Center, CUNY City College of New York / Electrical Engineering Department, CUNY City College of New York)

Vertical Wind Patterns in the NYC Built Environment: Wind LIDAR Observations of Dispersion and Downburst Behavior

The complex dynamics of the New York City built environment present many challenges to public agencies responsible for assessing air quality, and infrastructure resilience to extreme weather events. The City College of New York’s suite of remote sensing observations including a Doppler wind LIDAR system, Micro Pulse LIDAR (MPL), ceilometer, and microwave radiometer have aided researchers in improving the understanding and modeling of weather and air quality for hazardous events. Over the course of a seven-month period incorporating the late spring, summer, and early autumn, the ORSL implemented a number of measurement strategies including PBL height measurements, VAD, and vertical stares to increase understanding of wind shears, and their effects on air pollution transport and infrastructure. Initial results indicate that an integrated approach to urban observations is necessary for robust air quality monitoring during extreme weather events.

9:25 - 9:45

Antenna Efficiency Optimization in Coherent Lidar Systems

Sammy W. Henderson (Beyond Photonics)

Antenna Efficiency Optimization in Coherent Lidar Systems

Maintaining very high antenna efficiency is crucial in achieving a high level of performance from coherent lidar systems. This is especially important for space-based operation where available spacecraft prime power limits the transmitter power that can be utilized. We review the impact of wavefront aberrations and misalignment, including lag angle misalignment, on the performance of coherent lidar systems and describe requirements for achieving high antenna efficiency. A lagangle compensation system is described allowing maintenance of high lidar efficiency in largeaperture space-based and coherent lidar systems. Convenient analytic expressions we have developed will also be described, which approximate well the antenna efficiency of truncated Gaussian beams when wavefront aberrations and misalignment are present, and which allow for improved physical understanding and faster coherent lidar design trades.

9:45 - 10:05

Amplification of the mean echo signal power of coherent lidar in a turbulent atmosphere

Viktor A. Banakh (Institute of Atmospheric Optics, Siberian Branch of the Russian Academy of Sciences) and Andrey V. Falits (Institute of Atmospheric Optics, Siberian Branch of the Russian Academy of Sciences)

Amplification of the mean echo signal power of coherent lidar in a turbulent atmosphere

The results of measurement of the mean signal power of the Stream Line (Halo Photonics) lidar on a horizontal path when scattering of a probing beam on a screen located 500 m from the lidar under different turbulent conditions in the atmosphere are presented. It is established that under conditions of developed turbulence, the increase in the average power of the lidar signal occurs simultaneously with the increase in the magnitude of the structural constant of the turbulent fluctuations of the refractive index of air in the atmosphere. It is demonstrated based on the computer simulation that such a behavior of the average power of the echo signal of a coherent lidar can be a consequence of the effect of backscatter amplification in random media which occurs when probing in a turbulent atmosphere due to correlation of the probing and scattered waves because they pass through same refractive index inhomogeneities.

10:05 - 10:25 Coffee Break
10:25 - 11:35

Lidars & measurements for wind energy I

Chairman : Jean-Pierre Cariou (Leosphere)

10:25 - 10:50 Invited

Scanning Doppler lidars for Wind Energy research and validation of NWP model wind forecast in complex terrain

Yelena L. Pichugina (Cooperative Institute for Research in Environmental Sciences / Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Alan Brewer (Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Robert Banta (Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Aditya Choukulkar (Cooperative Institute for Research in Environmental Sciences / Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Timothy Bonin (Cooperative Institute for Research in Environmental Sciences / Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Joseph Olson (Cooperative Institute for Research in Environmental Sciences / Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Jaymes Kenyon (Cooperative Institute for Research in Environmental Sciences / Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Melinda Marquis (Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Christina Bonfanti (Cooperative Institute for Research in Environmental Sciences / Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Brandi Mccarty (Cooperative Institute for Research in Environmental Sciences / Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Sunil Baidar (Cooperative Institute for Research in Environmental Sciences / Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Scott Sandberg (Cooperative Institute for Research in Environmental Sciences / Earth System Research Laboratory, National Oceanic and Atmospheric Administration), AnnWeickmann (Cooperative Institute for Research in Environmental Sciences / Earth System Research Laboratory, National Oceanic and Atmospheric Administration), Harindra Fernando (University of Notre Dame), Raghavendra Krishnamurthy (University of Notre Dame), and Joel Cline (Department of Energy)

Scanning Doppler lidars for Wind Energy research and validation of NWP model wind forecast in complex terrain

Measurements from scanning Doppler lidars at three sites in Columbia River Gorge during the second Wind Forecast Improvement Project (WFIP-2) are used to analyze the temporal and siteto-site variability of the wind profile, to better understand physical processes related to the terrain effects, weather conditions, and presence of wind farms. Continuous measurements from two 200S lidars for 18-months and year-long measurements from a StreamLine lidar provide a comprehensive dataset to validate NWP model wind forecasts and evaluate model accuracy over days, months and seasons, as well as for periods of interesting meteorological events including wind ramps, cold fronts, or marine push in the study area. Verification metrics such as bias, RMSE, MAE, and the correlation coefficient between observed and modeled wind variables are analyzed as a function of height, time, and forecast hour, revealing meteorological features that are not well represented by models and providing insight to potential model improvements.

10:50 - 11:15 Invited

Synchronized Agile Beam Scanning of Coherent Continuous-Wave Doppler Lidar Technologies for High-ResolutionWind Field Characterization

Mikael Sjoholm (Technical University of Denmark, DTU Wind Energy, Campus Riso, Frederiksborgvej 399, DK-4000 Roskilde, Denmark), Nikolas Angelou (Technical University of Denmark, DTU Wind Energy, Campus Riso, Frederiksborgvej 399, DK-4000 Roskilde, Denmark), Michael Courtney (Technical University of Denmark, DTU Wind Energy, Campus Riso, Frederiksborgvej 399, DK-4000 Roskilde, Denmark), Ebba Dellwik (Technical University of Denmark, DTU Wind Energy, Campus Riso, Frederiksborgvej 399, DK-4000 Roskilde, Denmark), Jakob Mann (Technical University of Denmark, DTU Wind Energy, Campus Riso, Frederiksborgvej 399, DK-4000 Roskilde, Denmark), Torben Mikkelsen (Technical University of Denmark, DTU Wind Energy, Campus Riso, Frederiksborgvej 399, DK-4000 Roskilde, Denmark), and Anders T. Pedersen (Technical University of Denmark, DTUWind Energy, Campus Riso, Frederiksborgvej 399, DK-4000 Roskilde, Denmark)

Synchronized Agile Beam Scanning of Coherent Continuous-Wave Doppler Lidar Technologies for High-ResolutionWind Field Characterization

Developments of coherent continuous-wave lidar technologies for detailed studies of the three wind components of wind fields in the three-dimensional space has been pursued at DTU Wind Energy during the last decade with a concept called WindScanner. Since a single lidar only measures the wind component along the laser beam, the concept builds on synchronized agile beam-scanning of several lidars. The talk will review the technological developments including synchronized double-prism-based scanning and an all-fiber in-phase and quadrature direction detection scheme. Several different instrument implementations have been realized and application examples from wind energy, structural design, aviation, boundary-layer meteorology, and recently also forestry and detailed studies in wind tunnels will be highlighted. The wind lidar developments has not only proven to provide useful remote-sensing tools for wind field characterization at high spatial and temporal resolution but also holds prospects as tools for calibrating traditional point-monitoring anemometric devices which currently is investigated.

11:15 - 11:35

Development and testing of a triple-beam Doppler lidar system for 3D wind measurement

Matthew S. Warden (Fraunhofer Centre for Applied Photonics), Simon T. Sørensen (Fraunhofer Centre for Applied Photonics), John Macarthur (Fraunhofer Centre for Applied Photonics), Mark Silver (Thales UK), Theodore C. Holtom (Wind Farm Analytics Ltd.), Craig McDonald (Wood), Peter J. M. Clive (Wood), and Henry T. Bookey (Fraunhofer Centre for Applied Photonics)

Development and testing of a triple-beam Doppler lidar system for 3D wind measurement

We present results from our recent development of a triple-beam Doppler lidar system for accurate 3-dimensional wind measurements. The eye-safe all-fibre system consists of a central ‘hub’ unit and three spatially separated ‘emitter’ units. The hub contains a single seed laser that is shared between the emitters. Each emitter has its own optical amplifier, Risley prism beam steerer, and heterodyne detector. The photodiode signals are digitised and analysed centrally in the hub. The three lidar emitters were verified against each other and a calibrated met mast at Myres Hill near Glasgow. To test the converging beam methodology, the three emitter units were arranged in an equilateral triangle with an 8 m distance from each to the hub and the three beams were brought to intersect at a height of 60 m. Steps towards wind turbine blade integration will be outlined.

11:35 - 12:55 Lunch Break
12:55 - 15:05

Ground-based and airborne lidars I

Chairman : Benjamin Witschas (DLR)

12:55 - 13:20 Invited

Airborne wind and backscatter measurements during the A-Life campaign in Cyprus

Stephan Rahm (DLR Deutsches Zentrum fur Luft und Raumfahrt), Fernando Chouza (Univerity of Vienna), Oliver Reitebuch (DLR Deutsches Zentrum fur Luft und Raumfahrt), and Benjamin Witschas (DLR Deutsches Zentrum fur Luft und Raumfahrt)

Airborne wind and backscatter measurements during the A-Life campaign in Cyprus

At the A-LIFE campaign 2017 in Cyprus the well-known DLR 2-micron Doppler Lidar has been integrated into the research aircraft Falcon F20 together with an extensive number of in situ sensors from DLR and the University of Vienna. Main objective of the campaign was the investigation of aerosol properties, mainly mineral dust and black carbon mixtures. The Doppler lidar was used to gather information about the extension of those dust (aerosol) layers as well as to estimate the mass transport. At each flight one or more altitude profile(s) was done to gather aerosol information with the in situ sensors. Subsequently the to calibrate the Doppler Lidar in terms of Backscatter a calibrated aerosol lidar of the LMU Munich was overflown at nearly each flight. This paper will give an overview of all flights and focus on one Saharan dust outbreak for details.

13:20 - 13:45 Invited

Overview of Demonstration Project of JAXA Onboard Turbulence Detection System

Shigeru Machida (Japan Aerospace Exploration Agency), Hamaki Inokuchi (Japan Aerospace Exploration Agency), and Naoki Matayoshi (Japan Aerospace Exploration Agency)

Overview of Demonstration Project of JAXA Onboard Turbulence Detection System

Aircraft Accident and Incident Reports published by Japan Transport Safety Board show that turbulence is the leading cause of in-flight injuries during the past 20 years. In order to conduct R&D to reduce injuries penetrating a clear air turbulence, the JAXA R&D project team was formed in 2014. The team had successfully developed the onboard clear air turbulence detection system that weighs only 83.7 kilogram. In 2017, the system has been demonstrated using an experimental small jet aircraft that the LIDAR has a capability to observe air turbulence at a distance of 17.5 km (Ave.) which is the world’s longest detection range. The advisory function has been also demonstrated, which can provide turbulence information to pilots. This innovative solution is selected as one of technologies to be tested on the ecoDemonstrator program 2018 by The Boeing Company. In this paper, project overview, flight test and next steps are described.

13:45 - 14:05

Heterodyne high-spectral-resolution lidar

Fernando Chouza (German Aerospace Center (DLR)), Benjamin Witschas (German Aerospace Center (DLR)), and Oliver Reitebuch (German Aerospace Center (DLR))

Heterodyne high-spectral-resolution lidar

This study presents a novel lidar technique to conduct high-spectral-resolution measurements of the atmospheric backscatter. The proposed method, based on a heterodyne detection receiver, allows the separation of the molecular and the aerosol component of the atmospheric backscatter, as well as the analysis of the spectral shape of the Rayleigh-Brillouin line. As in the case of the direct-detection high-spectral-resolution lidars (HHSRLs), the separation of the different scattering processes allows an independent system calibration and aerosol extinction measurements. The proposed measurement technique was successfully tested on the DLR airborne Doppler wind lidar system based on data collected during different campaigns and under different atmospheric conditions. In light of these results, further ideas for the implementation of a dedicated HHSRL will be discussed.

14:05 - 14:25

Onboard wake vortex localisation with a fibered Coherent 1.5µm Doppler Lidar for aircrafts in formation flight

Agnes Dolfi-Bouteyre (ONERA), Didier Goular (ONERA), Beatrice Augere, Christophe Planchat (ONERA), Didier Fleury (ONERA), Laurent Lombard (ONERA), Matthieu Valla (ONERA), Anne Durecu (ONERA), and Claudine Besson (ONERA)

Onboard wake vortex localisation with a fibered Coherent 1.5µm Doppler Lidar for aircrafts in formation flight

In this paper, we present the development of an on-board LIght Detection And Ranging (LIDAR) sensor, based on pulsed 1.5µm fibered laser for wake vortex localisation for aircrafts in formation flight. The originality of the sensor is its very short range detection capability (<30m) and its high frame rate (0.25Hz). A 100ns laser pulse has been developed and an end-to-end Doppler heterodyne LIDAR simulator has been used for LIDAR design taking into account observation geometry, wake vortex velocity field, wind turbulence, scanning pattern, LIDAR response (including blind zone) and signal processing. The Lidar has been successfully operated on board a test aircraft while a wake generator aircraft was flying ahead. The LIDAR real-time display includes a 2D velocity map which has enabled the test flight engineer to localise vortex position. Exact positions of the vortex cores are automatically post processed with an accuracy estimated better than 2m.

14:25 - 14:45

Analytical Feasibility Study of Wind Lidar with Long-Duration FrequencyModulated Pulse

Eiichi Yoshikawa (Japan Aerospace Exploration Agency / Tokyo Metropolitan University), Tomoo Ushio (Tokyo Metropolitan University), and Hiroshi Yamasuge (Tokyo Metropolitan University)

Analytical Feasibility Study of Wind Lidar with Long-Duration FrequencyModulated Pulse

A wind lidar which transmits a laser pulse with long duration and frequency modulation is proposed. The transmitted laser signal is emitted to aerosol media flowing with wind, and scattered signal with Doppler frequency shift is received. The received signal is digitized, and processed by the matched filter method. The matched filter method, however, filters out the received signal even with a Doppler frequency shift of few meter per second because Doppler frequency shift is very large in optical frequency. The proposed wind lidar, therefore, prepares multiple reference signals with presupposed Doppler frequency shifts, and multiply performs the matched filter method by using the reference signals. Performances of the proposed wind lidar is analytically evaluated as radial velocity estimates improve in proportion to the square root of pulse duration.

14:45 - 15:05

The Scheimpflug Lidar Technique and Its Recent Progress in Atmospheric Remote Sensing

Liang Mei (Dalian University of Technology), Zheng Kong (Dalian University of Technology), and Peng Guan (Dalian University of Technology)

The Scheimpflug Lidar Technique and Its Recent Progress in Atmospheric Remote Sensing

The Scheimpflug lidar (SLidar) technique has been recently developed for atmospheric remote sensing. By transmitting a continuous-wave (CW) laser beam into atmosphere, the entire laser beam over km-range can be clearly focused on a tilted image sensor, while the optical configuration satisfies the Scheimpflug principle. The range-resolved lidar signal is in this case angularresolved. The fundamentally different principle enables the usage of low-cost, compact highpower CW laser diodes and highly integrated CMOS/CCD image sensors. This work presents our recent studies of the SLidar technique: (1) Development and validation of the 405-nm, 450-nm, and 520-nm SLidar systems for atmospheric remote sensing; (2) The development and case studies of a polarization SLidar technique; (3) NO2 remote sensing by employing the CW differential absorption lidar technique, where a ppb-level sensitivity is achieved by using a low-cost multimode 450-nm laser diode.

15:05 - 15:25 Coffee Break
15:25 - 16:50

Imaging, acoustic sensing, and novel sensing I

Chairman : Kevin W. Holman (MIT Lincoln Laboratory)

15:25 - 15:50 Invited

Ultrahigh accuracy distance measurements with self-correction of the airrefractive index using optical frequency combs

Kaoru Minoshima (The University of Electro-Communications / JST, ERATO MINOSHIMA Intelligent Optical Synthesizer)

Ultrahigh accuracy distance measurements with self-correction of the airrefractive index using optical frequency combs

High-accuracy long-distance measurements are essential for many applications. For practical distance measurements in atmosphere, the air refractive index is one of the most important sources of uncertainties. However, correcting the air refractive index along the exact optical path under measurement is difficult. By length measurements using lasers of two different colors, dispersion relation for air refractive index can be used for the self-correction of the air refractive index, i.e., two-color method. In this talk, two types of ultrahigh-accuracy two-color method using optical frequency comb are presented. First, using the fundamental and second-harmonic wavelengths generated from a Er:fiber comb, two-color self-correction was performed, exceeding the accuracy provided by the empirical equations. In the second method, the pulse envelope and the carrier phase are used to determine the optical distances to realize an equivalent method to the two-color method but at a single color, leading to the accuracy of 10-8.

15:50 - 16:10

Low Coherence Doppler Lidar with High-power DFB-LD

Tatsuo Shiina (Graduate School of Engineering, Chiba University)

Low Coherence Doppler Lidar with High-power DFB-LD

A compact Doppler lidar was developed with a unique DFB-LD. This DFB-LD is a bulk device with the CW power of 2.7W[max] and the center wavelength of 976nm. Its spectrum width is about 10ps[max]. Coherence length and output power was optimized to 0.8m and 1.76W respectively by adjusting device temperature and forward current. A low coherence Doppler lidar system was designed with this unique device. The concrete lidar setup was fabricated with an optical fiber interferometer and a differential amplifier. The Doppler echo of the wind at the measurement path distance, which is matched with the reference path distance, is detected and interfered with the reference light. In the experiment, rotating reflector was utilized as wind, its rotating speed of 1 - 10m/s was measured with the accuracy of 0.03m/s. Mist flow was measured with this lidar system. the system sensitivity and the detectable maximum distance were estimated.

16:10 - 16:30

Micro crack analysis of optical fiber by specialized TD-OCT

Masayuki Tanaka (Chiba University) and Tatsuo Shiina (Chiba University)

Micro crack analysis of optical fiber by specialized TD-OCT

We have developed a method to evaluate absolute value of return loss on optical fiber in the optical connector using the specialized TD-OCT. The absolute measurement of the return loss could be performed with an error of ±3 dB in the range of 10 to 100 dB. As a result, micro crack of the optical fiber could be evaluated quantitatively. Furthermore, the state of the micro crack which could not be detected in the past could be analyzed without taking the product apart. If the value of the return loss and the elapsed time from the manufacturing are known, the angle of micro crack of the optical fiber and presence or absence of the gap between the fracture surfaces will be estimated.

16:30 - 16:50

A comb heterodyne receiver on a geosynchronous satellite? for long-path absorption measurements of atmospheric trace gases: a feasibility study

Nobuo Sugimoto (National Institute for Environmental Studies)

A comb heterodyne receiver on a geosynchronous satellite? for long-path absorption measurements of atmospheric trace gases: a feasibility study

We performed an experiment on laser long-path absorption measurements using a retroreflector on a polar-orbit satellite (the Retroreflector in Space Experiment with ADEOS in 1996). It was an exciting experiment as a technical demonstration, but it was not an efficient method for atmospheric observations. Actually, our original concept of earth-to-satellite laser long-path absorption measurements was a system using a detection system on a geosynchronous satellite. It is much more efficient, and a high-power laser transmitter and a large-diameter satellite-tracking telescopes are not required in the ground station. Various types of measurement systems can be considered with direct detection receivers on a satellite. However, a better idea would be applying dual comb spectroscopy. We may have a comb heterodyne receiver on a geosynchronous satellite and send a comb beam from the ground station. This paper discusses advantages of the active methods compared with passive ground-based spectrometers, and problems.

16:50 - 18:50

Poster session (Meeting Room #1)

Chairman : Makoto Abo (Tokyo Metropolitan University), Tatsuo Shiina (Chiba University)

Day 2

16:50 - 18:50

Poster session (Meeting Room #1)

Chairman :Makoto Abo (Tokyo Metropolitan University), Tatsuo Shiina (Chiba University)

P1

Comparison of FMCW-LiDAR system with optical- and electrical- domain swept light sources toward self-driving mobility application

Napat J.Jitcharoenchai (Tokyo Institute of Technology), Nobuhiko Nishiyama (Tokyo Institute of Technology), Tomohiro Amemiya (Tokyo Institute of Technology), and Shigehisa Arai (Tokyo Institute of Technology)

Comparison of FMCW-LiDAR system with optical- and electrical- domain swept light sources toward self-driving mobility application

The suitable configuration of FMCW-LiDAR to realize compact LiDAR system on Si-photonics platform for self-driving mobility application is investigated. Especially, signal comparison with two types of wavelength swept light sources will be discussed in the presentation. One is an optical-domain thermally wavelength-tuned laser by sweeping injection current. The other is an electrical-domain wavelength-tuned source by the combination of a CW laser with an external modulator which superimposes electrical frequency shift. Signals and 3-dimentional images were taken and compared using two light sources with fiber-based coherent detection setup. The results revealed similar signal-to-noise ratio and images for two configurations if applying k-clock resampling interferometer. Keywords FMCW-LiDAR, Swept light source, Self-driving application

P2

Synthetic Aperture Imaging Ladar Ground Test and Flight Demonstration

Yu Zhou (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), Zhiyong Lu (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), Jianfeng Sun (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), Qian Xu (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), Zu Luan (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), Lijuan Wang (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), Guangyuan Li (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), and Guo Zhang (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences)

Synthetic Aperture Imaging Ladar Ground Test and Flight Demonstration

This report describes the working principle, hardware and software structure and the first-round flight test results of the auto-heterodyne synthetic aperture laser imaging radar(ASAIL) demonstration system. At the same time, the results of the ground test with 10km distance of the modified synthetic aperture laser imaging radar system and the preliminary results of the inverse synthetic aperture laser imaging (ISAIL) of the UAV target are introduced. Finally, the improve proposals of auto-heterodyne synthetic aperture aperture laser imaging radar system and the future application directions of synthetic aperture laser imaging technology are discussed.

P3

A quantitative evaluation of skin phantom by skin OCT

Dilimulati Adili (chiba university) and Tatsuo Shiina (chiba university)

A quantitative evaluation of skin phantom by skin OCT

Optical coherence Tomography (OCT) is practically used in ophthalmology, but its quantitativeness is more valued for evaluation of human skin. In this study, Time-Domain typed Optical Coherence Tomography (TD - OCT) was specialized to evaluate human skins quantitatively, and skin phantom measurements were assessed. At first, skin phantoms at different concentrations were prepared and measured according to its representation of human skin. Same increment of the extinction coefficient was obtained as the increase of the concentration. The result was compared with the theoretical value derived from the transport mean free path among particles. It was considered as the effect of multiple scattering in the medium. Next, the measurement was performed on the human skin, and the extinction coefficients were discussed with skin phantoms’ results. Based on the linearity of the specialized TD-OCT, it can accurately represent biological information of human skin.

P4

FIB-SEM-EDS Analysis of Aerosols: Implications to Particle Optics

Vikas Goel (CSIR-National Physical Laboratory, New Delhi, India-110012 / Academy of Scientific and Innovative Research, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, India- 201002), Sumit K. Mishra (CSIR-National Physical Laboratory, New Delhi, India-110012 / Academy of Scientific and Innovative Research, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, India- 201002), Ajit S. Ahlawat (CSIR-National Physical Laboratory, New Delhi, India-110012 / Academy of Scientific and Innovative Research, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, India- 201002), Chhemendra Shrama (CSIR-National Physical Laboratory, New Delhi, India- 110012 / Academy of Scientific and Innovative Research, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, India- 201002), and Vijay N. Ojha (CSIR-National Physical Laboratory, New Delhi, India-110012 / Academy of Scientific and Innovative Research, Kamla Nehru Nagar, Ghaziabad, Uttar Pradesh, India- 201002)

FIB-SEM-EDS Analysis of Aerosols: Implications to Particle Optics

In retrieval techniques, aerosol generally considered as chemically homogeneous spheres which results in erroneous results. There is a severe need for multi-dimensional analysis of aerosol. Therefore, mineral dust particles were analyzed using focused ion beam(FIB) coupled with energy dispersive X-ray spectroscopy(EDS) and scanning electron microscopy(SEM). In present study, particle was observed in core-shell type structure, where shell was rich in Fe, Ca, C, Al, and Mg and core were rich in Si. In conventional SEM-EDS, particle was observed as homogeneous mixture of Ca, Si, Mg, C, Fe and Al. Single scattering albedo(SSA) was calculated using FIB-SEM-EDS results and conventional SEM-EDS, difference between two results was observed to increase with increasing wavelength and the highest difference was observed at 860nm i.e. 19.38%. This shows that homogeneous spheres assumption is putting 19.38% uncertainty in results, which could have a tremendous effect on radiative forcing estimations. Keywords-Radiation budget,FIB-SEM-EDS,Core-shell, SSA.

P5

Development of the monostatic fiber-based laser Doppler vibrometer using double-pass frequency shifter reducing the impact of internal reflection light and improving demodulation performance

Yuichi Nishino (Mitsubishi Electric Corporation, Information Technology R&D Center), Ryota Kojima (Mitsubishi Electric Corporation, Information Technology R&D Center), Masaharu Imaki (Mitsubishi Electric Corporation, Information Technology R&D Center), Takayuki Yanagisawa (Mitsubishi Electric Corporation, Information Technology R&D Center), and Shumpei Kameyama (Mitsubishi Electric Corporation, Information Technology R&D Center)

Development of the monostatic fiber-based laser Doppler vibrometer using double-pass frequency shifter reducing the impact of internal reflection light and improving demodulation performance

The fiber-based laser Doppler vibrometer is useful for many applications including the infrastructure health/condition monitoring, owing to its compactness, reliable components, eye-safety, and so on. However, the fiber-based configuration suffers from its internal reflection light which impacts the demodulation performance of vibration waveform, if the configuration is coaxial. Therefore, the past vibrometer must be bistatic to prevent this impact, and the sensitive alignment of the transmitter and receiver was needed. Here, we show the monostatic fiber-based vibrometer using the double-pass frequency shifter. This configuration realizes the discrimination of the internal reflection light and the received echo from the target without the above mentioned alignment. We developed the prototype and demonstrated its performance in sensing the road surface vibrations which were caused by passing vehicle. The demonstration implies the future application of this vibrometer to the road condition (sliding friction) monitoring for the traffic safety.

P6

Polarization maintaining, very-large-mode area, Er-doped fiber amplifier for high average power and high energy pulses

JeffreyW. Nicholson (OFS), Anthony Desantolo (OFS), Akira Fujisaki (OFS), Anand Hariharan (OFS), Anthony Yu (NASA Goddard Space Flight Center), and Mark Stephen (NASA Goddard Space Flight Center)

Polarization maintaining, very-large-mode area, Er-doped fiber amplifier for high average power and high energy pulses

Pulsed fiber lasers are limited in peak power and energy scaling by detrimental nonlinearities. To mitigate these nonlinearities, the effective area of the fiber can be increased, but can lead to multimode operation and a corresponding decrease in beam quality. In this work, we review progress in the development of a polarization-maintaining, very-large-mode-area (VLMA), Er-doped fiber laser for high pulse energy and high average power applications in the 1550 nm wavelength region. The fiber has an effective area of ~ 1000 square microns, allowing for high pulse energies. Core-pumping by a high power, Raman-fiber laser at 1480 nm helps achieve a diffraction limited M2. The VLMA-Er amplifier has been used to produce 600 micro-Joule, single frequency pulses at 1572 nm for CO2 LIDAR applications, as well as femtosecond pulses with over 100 W average power. Routes towards further pulse energy and power scaling will be discussed.

P7

Mid Infrared Superconducting Hot Electron Bolometer Mixers with nanoantennas

Akira Kawakami (NICT), Hisashi Shimakage (Ibaraki University), Junsei Horikawa (Fukui College), Masaharu Hyodo (Kanazawa University), Shingo Saito (NICT), Shukichi Tanaka (NICT), and Yoshinori Uzawa (NAOJ)

Mid Infrared Superconducting Hot Electron Bolometer Mixers with nanoantennas

To improve the response performance of mid-infrared (MIR) detectors, we designed and fabricated a superconducting hot electron bolometer mixer (HEBM) by using MIR-antenna technology. For designing MIR twin-slot-antenna and circuits, the surface impedance of Au thin films at cryogenic temperatures was evaluated. The HEBMs were formed with a superconducting strip, Au antenna, and distributed circuits, and the design frequency was set at 61.3 THz. We confirmed that the HEBM show responses with clear polarization dependence under MIR light irradiation. When the bias current was set near the critical current, dark pulses were observed under MIR irradiation, and the full width at half maximum of the dark pulse was evaluated to be approximately 0.21 ns. From these results, we considered that the MIR HEBM have 0.9 GHz IF-bandwidth.

P8

Demonstration of Athermal and Light-weight Optical Telescopes for Airborne LIDAR System

Akihiro Fujie (Mitsubishi Electric Corporation), Yoshichika Miwa (Mitsubishi Electric Corporation), Hitomi Ono (Mitsubishi Electric Corporation), Jiro Suzuki (Mitsubishi Electric Corporation), and Toshiyuki Ando (Mitsubishi Electric Corporation)

Demonstration of Athermal and Light-weight Optical Telescopes for Airborne LIDAR System

Recently, primary cause of aircraft accident is the unexpected turbulence. We are developing airborne LIDAR (Laser Imaging Detection and Ranging) system which operates in eye-safe wavelength (λ=1.55 µm). In this system, optical telescope is required to be small, light-weight, and insensitive to temperature and pressure change in flight. In this paper we have made athermal design of light weight optical telescope with CFRP (Carbon Fiber Reinforced Plastic) structures taking into consideration of CTE of CFRP. We also evaluated their optical performance by a Shack- Hartmann wavefront sensor. Furthermore, we achieved 70% weight reducing in large diameter telescope and demonstrated the validity of the athermal designing by experiment that simulated flight environment.

P9

Development of conductively cooled, Q-switched Tm,Ho:YLF MOPA system

Makoto Aoki (National Institute of Information and Communications Technology), Atsushi Sato (National Institute of Information and Communications Technology / Tohoku Institute of Technology), Shoken Ishii (National Institute of Information and Communications Technology), Kohei Mizutani (National Institute of Information and Communications Technology), and Minoru Kubota (National Institute of Information and Communications Technology)

Development of conductively cooled, Q-switched Tm,Ho:YLF MOPA system

A conductively cooled, diode-pumped, Q-switched Tm,Ho:YLF master oscillator and power amplifier (MOPA) was developed for coherent lidar applications. By optimizing laser rod parameters and oscillator configurations, the oscillator output energy of 74 mJ with a pulse width of 120 ns and a near-diffraction-limited beam quality was obtained at 30 Hz and -40°C. As a single-pass amplifier, the pulses were amplified into 129 mJ pulses without the appearance of amplified spontaneous emission. Injection-seeded, single-frequency operation was achieved without any loss of the pulse energy owing to adoption of a ring resonator for the oscillator.

P10

Measurements of water vapor profiles with compact DIAL for local heavy rainfall prediction in the Tokyo metropolitan area

Makoto Abo (Tokyo Metropolitan University), Tetsu Sakai (Meteorological Research Institute), Phong P. Hoai (Tokyo Metropolitan University), and Yoshinori Shoji (Meteorological Research Institute)

Measurements of water vapor profiles with compact DIAL for local heavy rainfall prediction in the Tokyo metropolitan area

In recent years, the frequency of occurrence of locally heavy rainfall that can cause extensive damages, has been increasing in Japan. For early prediction of the heavy rainfall, numerical weather model is employed using the conventional meteorological station data. However, the lead time and accuracy of the prediction are limited because of the coarse spatial and temporal resolutions of the data. To improve them, it is useful to measure the water vapor distribution upwind cumulus convection beforehand and assimilate the data into the model. For that purpose, we have been developing compact NIR water vapor differential absorption lidar (DIAL).We show the results of the measurements with lidar in summer when the local heavy rainfall frequently occurs in Japan.

P11

High peak power Doppler Lidar based on a 1.5µm compressive-strainedsinglemode fiber amplifier

Laurent Lombard (onera), Beatrice Augere (onera), Anne Durecu (onera), Didier Goular (onera), Francois Gustave (onera), Matthieu Valla (onera), and Agnes Dolfi-Bouteyre (onera)

High peak power Doppler Lidar based on a 1.5µm compressive-strainedsinglemode fiber amplifier

Wind Doppler coherent lidars based on pulsed single frequency fiber sources are usually limited by SBS (stimulated Brillouin Scattering) in the final fiber booster. This nonlinear effect limits the peak power achievable to around 50-100W in singlemode fibers, 200-300W in commercial LMA (large mode area) fibers and up to 2kW in specialty fibers. Onera has developed a patented SBS mitigation technique using compressive strain on fibers. This technique has been applied to a singlemode fiber amplifier and a peak power of up to 200W have been generated before the arising of SBS. This peak power is comparable to LMA fiber booster performances with additional advantages: the singlemode geometry allows using standard telecom fiber components and optimizes coherent mixing with the singlemode local oscillator. We will present the details of this technique, the achieved laser performances and tests results of a lidar using this compressive-strained-source.

P12

Improvement of SNR at near range using pulsed serrodyne technique on coherent laser transmitter for wind sensing lidar

Eisuke Haraguchi (Mitsubishi Electric Corp.), Hitomi Ono (Mitsubishi Electric Corp.), Akihiro Fujie (Mitsubishi Electric Corp.), and Toshiyuki Ando (Mitsubishi Electric Corp.)

Improvement of SNR at near range using pulsed serrodyne technique on coherent laser transmitter for wind sensing lidar

In the Coherent Doppler LIDAR (CDL), the minimum measurable range is restricted by the internal scattered light. We have developed Coherent Doppler LIDAR (CDL) system for wind sensing using a semiconductor optical amplifier (SOA) and an optical phase modulator operated at pulsed serrodyne modulation. In the pulsed serrodyne modulation, the amount of frequency shift within a single pulse can be arbitrarily changed. Using this technique, heterodyne beat signals from internal scattered light at near range are efficiently rejected by electrical bandpass filter. In this paper, we demonstrated the measurement of the scattered light from hard target at 40m distance within the internal scattered light by controlling the amount of frequency shift within a single pulse duration which pulse width is 500 ns.

P13

Development of the low-cost and high-performance coherent Doppler lidar system

Kuniaki Higashi (Metro Weather Co., Ltd.) and Jun-ichi Furumoto (Kyoto University)

Development of the low-cost and high-performance coherent Doppler lidar system

Metroweather Co., Ltd. and Kyoto University collaborates to develop the high-performance and low-cost coherent Doppler Lidar (CDL). This new lidar system enable us to detect the detailed structure of wake turbulence with the temporal resolution of < 10 seconds. The new CDL can also be applied to the dual observation to determine the horizontal wind components from several co-operated CDL data. The result of performance test and the potential of the new CDL will be presented in the session.

P14

First measurement results of water vapor profile using 1.53 micron coherent differential absorption LIDAR

Masaharu Imaki (Mitsubishi Electric Corporation), Kenichi Hirosawa (Mitsubishi Electric Corporation), Takayuki Yanagisawa (Mitsubishi Electric Corporation), and Shumpei Kameyama (Mitsubishi Electric Corporation)

First measurement results of water vapor profile using 1.53 micron coherent differential absorption LIDAR

We have been developed a ground based coherent differential absorption LIDAR for water vapor profile using 1.53 micron laser wavelength. A coherent lidar has an advantage in daytime measurement compared with incoherent lidar because the influence of background light is greatly low. In addition, the lidar can simultaneously measure wind speed and water vapor density. We demonstrated the water vapor measurements in horizontal range, and compared with in - situ sensor. The time variation of water vapor can be observed and the fluctuation of the measurement value in constant value region is about 0.8 g/m3 from the measurement results.

P15

Coherent Doppler LIDAR system switching the LOS direction by wavelength of laser

Nobuki Kotake (Mitsubishi Electric Corporation), Yojiro Watanabe (Mitsubishi Electric Corporation), Eisuke Haraguchi (Mitsubishi Electric Corporation), Shumpei Kameyama (Mitsubishi Electric Corporation), Toshiyuki Ando (Mitsubishi Electric Corporation), and Takayuki Yanagisawa (Mitsubishi Electric Corporation)

Coherent Doppler LIDAR system switching the LOS direction by wavelength of laser

The role of coherent Doppler LIDAR (CDL) systems for wind energy and airport safety is rapidly increased. The High reliability and the mass productivity are also increased because (1) the setting environment is sever (heavy rain, salt damage, etc.) and (2) the difficulty of replacement, in case used for turbine control. The conventional CDL uses the mechanical switch (wedge prism and motor,etc.) for switching the laser direction. We want to apply the passive switch to control the direction without mechanical devices for improving the reliability. Our goal is to realize non-mechanical LIDAR system using the uITLA for source light, WDM (for switching the optical path) which are used for the optical communication and a multi-beam direction telescope with several fiber adaptor. This telescope can switch the LOS direction by position of that adaptor. This system is easy to extend the number of LOS directions and to realize the simultaneous measurement.

P16

High efficiency all fiber coherent lidar for wind measurement

Anran Zhou (CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China), Yuli Han (CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China), Dongsong Sun (CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China), Fei Han (CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China), Jun Zheng (CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China), and Nannan Zhang (CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China)

High efficiency all fiber coherent lidar for wind measurement

Recently a high efficiency all-fiber coherent lidar system at 1.55 µm wavelength is developed to achieve real-time measurements of wind fields. The system employs 80 µJ pulse energy at 10 kHz pulse repetition rate. The lidar with compact and waterproof architecture is able to provide mobility, reliability, and ease of field deployment for wind measurements. Aerosol backscattering signals are obtained by a balanced detector and processed by a digital signal processor card in real time. And the high receiver efficiency provides for measurement range of wind fields up to 5km. Continuous wind profiles of the planetary boundary layer is presented to demonstrate the robustness and stability of the system.

P17

Experimental Verification of Wind Lidar with Long-Duration Frequency-Modulated Pulse

Hiroshi Yamasuge (Tokyo Metropolitan University), Eiichi Yoshikawa (Japan Aerospace Exploration Agency), Tomoo Ushio (Tokyo Metropolitan University), Shoken Ishii (National Institute of Information and Communications Technology), Makoto Aoki (National Institute of Information and Communications Technology), and Kazuki Hashimoto (Japan Aerospace Exploration Agency)

Experimental Verification of Wind Lidar with Long-Duration Frequency-Modulated Pulse

In our previous research, a new wind lidar which has high power and high resolution by transmitting a laser pulse with long duration and frequency-modulation and demodulation was proposed. Analytical performance evaluation under ideal conditions had been done, which results in that accuracies of wind ranging and velocimetry increases in proportion to the square root of pulse duration. In this research, we investigated accuracy of modulated pulse shaping that is one of practical issues to realize the proposed wind lidar. We developed an experimental system which directly returns generated laser pulses to its receiver, and digitally measured the returned signal. Although, in the returned signal, the waveform changed compared to its ideal waveform, the result of matched filter processing showed practically sufficient performances that the mainlobe width was almost maintained, and peak power was reduced by -0.3 dB as compared with the ideal waveform.

P18

All semiconductor pulsed Doppler lidar for wind sensing

Jean-Pierre Cariou (LEOSPHERE, France), Vincent Pureur (LEOSPHERE, France), and Eric Hrywniack (LEOSPHERE, France)

All semiconductor pulsed Doppler lidar for wind sensing

Coherent Doppler lidars are usually powered by optical fiber amplifiers or solid state bulk amplifiers. Thanks to recent improvements semiconductor optical amplifiers (SOA), we have demonstrated the first 1.5µm all solid state Doppler pulsed lidar for wind sensing. Low pulse energy typically available in SOAs is balanced by high pulse repetition frequency, allowing range resolved measurement of wind from 40m to 200m with 20m range resolution. The SOA is also used as a pulse shaper leading to a quite simple, compact and cost effective setup. First results are shown, and early atmospheric wind measurements are compared with a reference Windcube fibered lidar.

P19

Air-borne non-coherent Doppler lidar wind measurement ability simulation at low stratosphere

Decang Bi (Shanghai institute of optics and fine mechanics), Xiaopeng Zhu (Shanghai institute of optics and fine mechanics), Weibiao Chen, Jiqiao Liu (Shanghai institute of optics and fine mechanics), and Xiaolei Zhu (Shanghai institute of optics and fine mechanics)

Air-borne non-coherent Doppler lidar wind measurement ability simulation at low stratosphere

Air-borne non-coherent Doppler lidar is effective method for wind measurement. this paper simulate the measurement ability with 4 scanning direction at 25km altitude: 2m/s wind speed error under 2km distance, and 1.65m/s speed error under 4km distance. 4.8°wind direction error within 4km, 2m/s wind speed error with 10°direction error within 5km detection distance.

P20

A Study on the Convective Initiation by Combining Coherent Doppler Lidar and Large Eddy Simulation Model in the Urban Area

Naohiro Iwamoto (Research Institute for Sustainable Humanosphere, Kyoto University), Junichi Furumoto (Research Institute for Sustainable Humanosphere, Kyoto University), and Kuniaki Higashi (Research Institute for Sustainable Humanosphere, Kyoto University / MetroWeather Co., Ltd.)

A Study on the Convective Initiation by Combining Coherent Doppler Lidar and Large Eddy Simulation Model in the Urban Area

This study focused on the characteristics of convective initiation by combining Coherent Doppler Lidar (CDL) and Large Eddy Simulation (LES), aiming to explicate the developing mechanism of the active convective cell, which often causes localized heavy rainstorms. The convergence near the ground is one of the most important trigger of the convective activity. The data observed by CDL is useful to detect in detail convective field of the complicated surface region such as urban area. The CDL was installed at the top of 200m-height building at central of Tokyo and observed the radial wind velocity with the range resolution of 100m. The observed data were assimilated into the WRF (Weather Research and Forecasting) -LES model by using the four-dimensional variational assimilation method. The anomaly component of CDL-derived wind velocity was recognized. The model result showed the signature of near-surface convergence in prior to the convective activity.

P21

Feasibility study of data assimilation using a mobile water vapor Raman lidar

Satoru Yoshida (Meteorological Research Institute), Tetsu Sakai (Meteorological Research Institute), Tomohiro Nagai (Meteorological Research Institute), Sho Yokota (Meteorological Research Institute), Hiromu Seko (Meteorological Research Institute), and Yoshinori Shoji (Meteorological Research Institute)

Feasibility study of data assimilation using a mobile water vapor Raman lidar

Water vapor in atmosphere exerts strong influence on initiations and development of thunderstorms. Therefore, knowledge of water vapor distribution in atmosphere is useful for precipitation prediction with a use of data assimilation. Recently, water vapor assimilation using water vapor lidar systems which provides vertical profile of water vapor mixing ratio, has attracted attentions. Several studies showed a reduction of analysis errors in water vapor distribution using data assimilation of water vapor lidars. We have developed a mobile Raman lidar housed in a small trailer and studied the water vapor assimilation scheme for better weather forecast. Comparison of lidar results and collocated radiosonde results indicates that the water vapor mixing ratio measured with the lidar agrees well with radiosonde observations. Furthermore, we conducted water vapor assimilation experiment with a use of the water vapor mixing ratio measured with the lidar as a feasibility study.

P22

Retrieval of PM2.5 vertical distribution using the Doppler Lidar across NY Mesonet

Bhupal Shrestha (University at Albany) and Everette Joseph (University at Albany)

Retrieval of PM2.5 vertical distribution using the Doppler Lidar across NY Mesonet

The University at Albany has started Mesonet, a network of 17 enhanced sites across the NY state, comprised of Doppler Lidar, Microwave Radiometer and Sun Photometer. The goal of the network is to enhance information content by combining all sensors for NumericalWeather Prediction and air quality forecasting. The vertical profile of PM2.5 is very important for the study of air quality and its forecasting. There are several retrieval methods based mostly on AOD from satellite and Sun Photometer. All the retrieval methods are used to estimate surface PM2.5 only. In this study, the relationship of aerosol extinction coefficient retrieved from the Doppler Lidar with surface PM2.5 mass concentration is presented. Then, the PM2.5 profile is retrieved using the extinction coefficient profile. The retrieval technique is then applied throughout the network for real time 3D monitoring of PM2.5. Several case studies are presented.

P23

All-fiber wind lidar data processing technic

Gleb A. Petrov (JSC≪BANS≫/ Saint Petersburg Electrotechnical University LETI) and Nikolay A. Baranov (Dorodnicyn Computing Centre, FRC CSC RAS)

All-fiber wind lidar data processing technic

Wind profiler based on continuous laser source is considers in this work. This lidar allows to solve the task of wind profile restoration up to 300 m altitude. Increasing accuracy and speed of wind parameters calculation signal processing technics have been studied in this research. The problem is the frequency shift doesn’t depend on the wind velocity direction. Our approach is based on new fiber-optic scheme that is free of local oscillator element. This study shows the joint signal processing in one FFT module, which reduces the computational complexity and improves the energy efficiency due to joint processing of correlated signals. This spectrum analyzing makes it possible to determine both the positive and negative Doppler shift. Described technique: - simplifies the scheme of signal processing; - facilitates the search for Doppler frequency; - reduces computing requirements.

P24

Solar background noise for spaceborne lidar on specific orbits

Chuanliang Zhang (College of Meteorology and Oceanography, National University of Defense Technology, Nanjing, China), Xuejin Sun (College of Meteorology and Oceanography, National University of Defense Technology, Nanjing, China), Shijun Zhao (College of Meteorology and Oceanography, National University of Defense Technology, Nanjing, China), and Yanwen Liu (College of Meteorology and Oceanography, National University of Defense Technology, Nanjing, China)

Solar background noise for spaceborne lidar on specific orbits

Solar background noise is one of the main noise for the measurement of spaceborne lidar in daytime. For spaceborne Doppler wind lidar (DWL), the solar background radiation would introduce random error. In this paper, we quantified the global distribution of solar background noise on 355 nm and 532 nm using radiative transfer model (RTM) libRadtran for spaceborne DWL on specific orbit, and the orbit of Aeolus and International Space Station (ISS) was taken as an example. The bidirectional reflectance-distribution function (BRDF) was used to define the anisotropy surface reflectance on land, and the modified Cox and Muck model was used on ocean. The solar background noise varies with seasons was also taken into consideration. The results shows the solar background noise have a big difference on different orbits.

P25

Discussion under generation range of non-diffracting beam transformed by annular beam in random media

Xiafukaiti Alifu (Chiba University), Ziqi Peng (Chiba University), Tatsuo Shiina (Chiba University), and Hiroaki Kuze (Chiba University)

Discussion under generation range of non-diffracting beam transformed by annular beam in random media

When an annular beam was used as lidar transmitted beam in atmosphere, it can make the influence of the atmosphere fluctuation smaller than a Gaussian beam, because the annular beam can self-transform to the non-diffracting beam. However, in general, light is hard to propagate at long distance in random media such as cloud or haze, due to strong scattering of particles. In this paper, the annular beam (diameter:40mm) was propagated in random media (diluted processed milk, milk fat: 1.8%) and the receiving waveform was detected by a narrow view angle of 5.5mrad. The non-diffracting beam was successfully generated at the short distance of 3cm 5cm in random media with high concentration of 2% 23%. It was generated in wider concentration range at shorter distance in random media with higher concentration. The generation range could be estimated at arbitrary propagation distance by these known results.

P26

End-to-end simulation of a coherent lidar in a turbulent wind field

Jean-Pierre Cariou (LEOSPHERE, France), Ludovic Thobois (LEOSPHERE, France), and Sebastien Combrexelle (LEOSPHERE, France)

End-to-end simulation of a coherent lidar in a turbulent wind field

For operational applications such as wind resource assessment or turbine control, to warranty the performances in velocity accuracy and data availability is required. A LIDAR simulator (SimulidTM) has been developed for assessing the velocity accuracy and the data availability of pulsed coherent wind Doppler LIDAR system worldwide. This simulator takes into account both the LIDAR parameters (instrument hardware, signal processing, beam propagation  ) and the aerosol properties. Recently, SimulidTM has been coupled with a 3D wind model (Turbsim) to perform simulated wind measurements in any representative wind field, including shear and turbulence. We present the methodology and the validation process. Simulated range is compared to actual data. Velocity accuracy is compared with analytical models, with experimental tests performed in a frozen propagation medium, and with spectral analysis of true atmospheric wind data.

P27

Application of piecewise AR model estimation for approximate stationary process in decision of pulse number and range gate

Qizun Zhang (Beijing Institute of Technology), He Chen (Beijing Institute of Technology), Siying Chen (Beijing Institute of Technology), Pan Guo (Beijing Institute of Technology), and Yinchao Zhang (Beijing Institute of Technology)

Application of piecewise AR model estimation for approximate stationary process in decision of pulse number and range gate

The algorithm for wind field data inversion of CoherentWind Lidar usually uses PP, PM and ML. The premise of those algorithms is to assume that the echo signal is approximately stationary. If the pulse count is sufficiently large and the range gate is short enough, the signal is considered to be nearly stationary, but increasing the accumulated pulse number will reduce the temporal resolution and reducing the range gate length will increase the inversion error. In order to ensure the resolution of the signal without loss of accuracy, the Bayesian method based on the autoregression (AR) model is used to transform the non-stationary echo signal into a piecewise stationary signal. By using this method the optimal number of accumulated pulses and the optimal range gate division could be obtained effectively, so the resolution and accuracy of the inverse wind field can be ensured at the same time.

P28

Vertical Velocity Statistics and Turbulence Characterization by Coherent Doppler Lidar over Coastal Area

Songhua Wu (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China / Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology), Xiaochun Zhai (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China), Xiaoquan Song (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China / Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology), and Xiaoying Liu (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China)

Vertical Velocity Statistics and Turbulence Characterization by Coherent Doppler Lidar over Coastal Area

This paper gives an overview of the statistics of vertical velocity and atmospheric turbulence from a ground-based zenith-pointing Doppler lidar deployed over coastal area close to the South China Sea. Two-month outfield experiment from Sep 2 2017 to Nov 1 2017 is firstly introduced. The time series of vertical velocity are used to calculate the atmospheric integral scale and higherorder moment, giving useful information about the structure of turbulence in the atmospheric boundary layer (ABL). The updraft and downdraft characteristics at different atmospheric conditions, including convective and neutral boundary layer, are also analyzed and compared, which can provide valuable information to improve our understanding of physical processes of organized convection in the ABL and to further improve and validate vertical flux schemes of atmospheric models. The cloud effect on atmospheric dynamic process over ABL is also discussed and compared with the previous literature. Keywords:MABL, turbulence, vertical velocity, atmospheric dynamics

P29

Lidar Observation of Wind Shear along Glide Path at Beijing Capital International Airport

Hongwei Zhang (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China), Songhua Wu (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China / Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology), and Qichao Wang (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China)

Lidar Observation of Wind Shear along Glide Path at Beijing Capital International Airport

The significance of wind shear to aviation lies in its effect on aircraft performance and hence its potentially adverse effect on flight safety during landing phase especially within 500m (1600 ft) at height. The lidar team in Ocean University of China (OUC) carried out the particular research of the low level wind shear along the glide path at Beijing Capital International Airport (BCIA) in 2016 by utilizing a pulse coherent Doppler lidar (PCDL) system. On account of the high spatial and temporal resolution, the small-scale air mass disturbances along the glide path can be captured easily. The experiment configuration, the PCDL system, case study and the statistics of wind shear intensity are proposed and experimentally demonstrated. The reliability of wind shear identification algorithms has been proved by wind shear reports from the crew and the terminal control office. Key words: coherent lidar, wind shear, civil aircraft safety

P30

TheWind Observation over Sea Surface by UAV-borne Coherent Doppler Lidar

Qichao Wang (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China), Songhua Wu (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China / Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology), Jintao Liu (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China), Kailin Zhang (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China), and Bingyi Liu (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China / Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology)

TheWind Observation over Sea Surface by UAV-borne Coherent Doppler Lidar

The accurate and rapid wide-range observation of ocean surface wind data is important for the research of ocean dynamic prediction model, offshore wind resource assessment, air-sea interaction and flux. A compact UAV-borne Coherent Doppler Lidar (UCDL) has been developed by the Ocean University of China for the observation of wind profile and boundary layer structure in Marine Atmospheric Boundary Layer (MABL), and the first flight campaign has been completed in Hailing Island in December 2016. The motion-correction and wind data processing methodology of the UCDL are expounded in detail. Further, the sea surface backscatter signals are used to process the wind data and the results of the first flight campaign processed by two wind-correction methods are compared and validated with a ground-based coherent Doppler lidar. Meanwhile, the characteristics of the wind data will be discussed as well. Keywords : UCDL, Motion-correction, Wind data processing

P31

Up to 12 km vertical wind profiling using Mitsubishi Electric’s long range lidar

Ikuya Kakimoto (Mitsubishi Electric Corporation), Taiji Harada (Mitsubishi Electric Corporation), Shumpei Kameyama (Mitsubishi Electric Corporation), Jong-Sung Ha (Korea Aerospace Research Institute), and Hong-Il Kim (Korea Aerospace Research Institute)

Up to 12 km vertical wind profiling using Mitsubishi Electric’s long range lidar

Mitsubishi Electric’s wind lidar “DIABREZZA A series” has been deployed for microburst / wind shear detection for several international airports such as Tokyo, Narita, Hong Kong. And MELCO has recently made a contract with Beijing New International Airport and scheduled to deliver in 2018. In addition to the usual functions for the airport application, a new function for vertical wind profiling has been developed in response to the requirement from KARI (Korea Aerospace Research Institute). The observation performance evaluation by data comparison with DIABREZZA and radio sonde or ground wind sensors were carried out by KARI, and the result shows that DIABREZZA has observation performance up to height of 12 km in no precipitation condition. The correlation coefficient of wind speed between DIABREZZA and radio sonde was 0.98 and that of wind direction was 0.87. This implies the expanding use of wind lidars for high altitude wind sensing.

P32

Comparison of wind measurements between virtual tower and VAD methods

Songhua Wu (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China / Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology), Xiaoying Liu (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China), Hongwei Zhang (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China), Qichao Wang (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China), and Xiaochun Zhai (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China)

Comparison of wind measurements between virtual tower and VAD methods

with different elevation angles This paper compares wind retrieval methods of VT (Virtual Tower) mode and VAD (Velocity- Azimuth Display) with different scanning elevation angles. The field experiment was performed from September 23 to October 13 2017 at the campus of Ocean University of China under various weather conditions. A total of seven lidars were involved in the experiment. Three lidars carried out the staring mode to constitute the VT . The other four lidars were concurrently operating PPI scan at different elevation angles, corresponding to different spatial average volume. The results of wind speed and direction from VT and VAD shows good correlation when lidars are well synchronized. The influence of spatial homogeneity on wind retrieval is also described in this paper.

P33

Physical model approach (PM) for the analysis of active sensor systems

Kaori Sato (Research Institute for Applied Mechanics, Kyushu University), Hajime Okamoto (Research Institute for Applied Mechanics, Kyushu University), Hiroshi Ishimoto (Meteorological Research Institute, Japan Meteorological Agency), and Shoken Ishii (National Institute of Information and Communications Technology)

Physical model approach (PM) for the analysis of active sensor systems

New ground-based lidars are being built based on the Multiple-Field-of-view Multipe-Scattering Polarization Lidar (MFMSPL) concept (Okamoto et al., 2016). Joint observations with Doppler lidars and cloud radar will be performed for the simulation of EarthCARE ATLID/CPR, Aeolus wind lidar, CALIPSO/CloudSat measurements to evaluate satellite retrieval algorithms for cloud/aerosol process studies. For the analysis of the joint observation system, a physical model (PM) that simulates the polarized multiple scattered space-borne lidar signals for input vertical profiles of cloud microphysics and air molecules as well as instrument settings such as the FOV has been developed (Sato et al., 2018). Error analyses by Monte Carlo simulations for CALIPSO and ATLID showed stability and advantage of the PM over more statistical approach. In this paper, application and extension of the PM for the simulation/analysis of the joint ground-based lidar system and satellite active sensors is studied.

P34

Atmospheric remote sensing by employing a blue-band continuous-wave lidar system

Hui Li (Dalian University of Technology), Zheng Kong (Dalian University of Technology), Zhi Liu (Dalian University of Technology), Lishan Zhang (Dalian University of Technology), Peng Guan (Dalian University of Technology), and Liang Mei (Dalian University of Technology)

Atmospheric remote sensing by employing a blue-band continuous-wave lidar system

A blue-band Scheimpflug lidar system is developed for atmospheric pollution monitoring. Atmospheric remote measurements were carried out for 10 days in urban area to validate the feasibility and performance of the Scheimpflug lidar system. 24-hour continuous measurement is achieved in winter on a near horizontal path with an elevation angle of 6.4°. The aerosol extinction coefficient retrieved by the Fernald-inversion algorithm shows good agreement with the variation of PM10/PM2.5 concentrations recorded by a local pollution monitoring station. The experimental result revealed that the linear ratio between the aerosol extinction coefficient and PM10 concentration under high moistures (75%-90%) is about 2-time of that in low moisture (≤75%) when PM10 concentrations are less than 100 µg/m3.

P35

Observations on Elevated Aerosol Layer Transport Using a Two Wavelength and Polarization LIDAR over A Tropical Rural Site, Gadanki (13.450 N, 79.170 E)

Vishnu R (National Atmospheric Research Laboratory, Gadanki, India / VIT University, Vellore, India), Bhavani Kumar Yellapragada (National Atmospheric Research Laboratory, Gadanki, India), and James J. Samuel (VIT University, Vellore, India)

Observations on Elevated Aerosol Layer Transport Using a Two Wavelength and Polarization LIDAR over A Tropical Rural Site, Gadanki (13.450 N, 79.170 E)

The Indian subcontinent is suffered from the elevated aerosol transport, which has a vital role in the air pollution monitoring. This article describes the observations carried out on the shape and size information of boundary layer aerosol particles using a two-wavelength and polarization lidar (TWPL) system developed indigenously at NARL, Gadanki during the transport period. The lidar system profiles the boundary layer at 1064 and 532 nm wavelengths and polarization measurements are conducted at 532 nm. The lidar system operates in the daylight period and provides information on scattering properties of boundary layer aerosols during convective hours. Two case studies on long-range transport that occurred during the year 2011 and 2012 are presented. The observations were compared with the simultaneous radiosonde measurements. We present the results in terms of aerosol back-scattering coefficient, depolarization ratio and color ratio with the support of back trajectory analysis.

P36

Rayleigh Lidar Observations of Tropical (13.5°N, 79.2°E) Mesospheric Inversion Layers: A Comparison between Dynamics and Chemistry

Karanam Ramesh (National Atmospheric Research Laboratory (NARL), Gadanki, A.P., India.), Sundararajan Sridharan (National Atmospheric Research Laboratory (NARL), Gadanki, A.P., India.), and Karnam Raghunath (National Atmospheric Research Laboratory(NARL), Gadanki, A.P., India.)

Rayleigh Lidar Observations of Tropical (13.5°N, 79.2°E) Mesospheric Inversion Layers: A Comparison between Dynamics and Chemistry

The Indo-Japanese Rayleigh lidar system installed at National Atmospheric Research Laboratory (NARL), Gadanki (13.5°N, 79.2°E), India has been operational since 1998 with 532 nm Nd: YAG green laser of energy 550 mJ/pulse (20 Hz PRF). The vertical temperature profiles are derived above 25 km using molecular back scattered photons assuming the atmosphere in hydrostatic equilibrium and obeys ideal gas law. The lidar system has been upgraded with a high power laser of energy 600 mJ/pulse (50 Hz PRF) in 2007 that significantly minimize the uncertainty in temperatures above 70 km. The lidar temperatures with high spatial (300 m) and temporal (250 sec) resolutions are used to study the vertical propagation characteristics of short period gravity waves and their role in the formation of mesospheric inversion layers (MILs). Further the roles of dynamics and chemistry are compared for the occurrence of MILs. Keywords: Rayleigh Lidar, Temperature, Gravity waves, Mesospheric Inversion Layer

Day 3

8:00 - 9:00 Reception and Registration
9:00 - 9:30

Special talk

Chairman : Michael Hardesty (University of Colorado Boulder)

9:00 - 9:30

Coherent Laser Radar in Japan, Past, Present and Future

Kazuhiro Asai (Tohoku Institute of Technology)

Coherent Laser Radar in Japan, Past, Present and Future

A research activity on coherent laser radar in Japan has begun in 1974. Kenya Goto, Tokyo Shibaura Electric Co.Ltd., had applied for a patent on “Doppler radar using laser” to United States Patent and Trademark Office(USPTO) and successfully acquired it. Since then, more than 200 papers written not only in Japanese and but also in English have been published by Japanese researchers until now. This paper is to describe on coherent laser radar activities in Japan, past, present and future.

9:30 - 11:15

Space-based lidars II

Chairman : Alain M. Dabas (Meteo-France)

9:30 - 9:55 Invited

Active Optical Remote Sensing Sensors and Instrumentations for NASA’s Future Earth Science, Planetary Science and Mars Explorations Measurements/Missions

Upendra N. Singh (NASA Langley Research Center)

Active Optical Remote Sensing Sensors and Instrumentations for NASA’s Future Earth Science, Planetary Science and Mars Explorations Measurements/Missions

Active optical (Laser/Lidar) is critical for future NASA Earth, Planetary Science, and Mars Explorations. Eight out of fourteen missions recommended by 2017 NRC Earth Science Decadal Survey require active optical remote sensing for successful mission implementation. Given the cross-cutting synergies in critical Active Optical measurements for NASA Science and Exploration, a strategic approach in needed to identify areas where NASA can lead, leverage and partner with existing national and international capabilities to meet its future needs. This presentation will focus on efforts being planned to assess the current capabilities of NASA for the Active Optical and identify opportunities and synergies with industry, academia, government agencies and international partners for NASA to address its critical gap areas and work with external capabilities to meet NASA Science and Exploration future needs for space-based active optical remote sensing applications.

9:55 - 10:15

Investigating Space-based Lidar Performance for Decadal Survey Science Objectives.

Michael Hardesty (CIRES University of Colorado Boulder), Sara C. Tucker (Ball Aerospace), Sunil Baidar (CIRES University of Colorado Boulder), Oliver Reitebuch (German Aerospace Center (DLR)), Stephan Rahm (German Aerospace Center (DLR)), and Benjamin Witschas (German Aerospace Center (DLR))

Investigating Space-based Lidar Performance for Decadal Survey Science Objectives.

The recent NRC Earth Sciences and Applications from Space Decadal Survey ranked 3-dimensional atmospheric winds as one of a number of “most important” observables. The report notes that winds would be transformative for weather and air quality forecasting in the boundary layer and free troposphere. Several space-based instrument performance simulations of notional instruments have been performed; however, most used theoretical models of atmospheric properties and system performance. Here, we reexamine performance models for direct-detection and coherent Doppler lidar systems, but also analyze observations from the Ball airborne OAWL and the DLR airborne coherent lidar to predict space-based system performance for Decadal Survey wind measurement scenarios. Data from flight campaigns are analyzed to investigate measurement capability, then scaled to predict performance of a space-based instrument seeing the same atmosphere. Based on these results we evaluate the suitability of similar instruments to address Decadal Survey scientific needs.

10:15 - 10:35

Space-based Coherent Lidar for Wind Measurements with High-Percentage Tropospheric Coverage

Sammy W. Henderson (Beyond Photonics)

Space-based Coherent Lidar for Wind Measurements with High-Percentage Tropospheric Coverage

We describe the potential for a 2-micron wavelength space-based coherent lidar system with power-aperture product and receiver efficiency sufficient to provide very high percentage coverage tropospheric wind vector measurements along two continuous stripes in the atmosphere below the satellite track. Lidar sensitivity is significantly enhanced by using an efficient lidar design and a 1.5m aperture diameter at 320km altitude (same as ESA Aeolus). An EO-tunable aperture (requiring aperture scaling development) toggles the lidar line of sight at the laser PRF sequentially across four lines of sight (fore and aft views for each of the two stripes). Wind measurements are possible to minimum backscatter coefficient of ~1e-10/m/sr for 1km vertical x 88km horizontal resolution, providing high-percentage coverage at acceptable resolution in the mid- and upper-troposphere; and to ~3e-9/m/sr for 100m vertical x 880m horizontal resolution, providing high-resolution measurements when higher backscatter is present.

10:35 - 10:55

Development of a coherent Doppler lidar for precision maneuvering and landing of space vehicles

Farzin Amzajerdian (NASA Langley Research Center), Glenn D. Hines (NASA Langley Research Center), Diego F. Pierrottet (Coherent Applications Inc.), Bruce W. Barnes (NASA Langley Research Center), Aram Gragossian (Coherent Applications Inc.), Mitchell J. Davis (NASA Langley Research Center), Tak-kwong Ng (NASA Langley Research Center), Alexander D. Scammell (NASA Langley Research Center), Adam Ben Shabat (NASA Langley Research Center), Larry B. Petway (NASA Langley Research Center), and John M. Carson Iii (NASA Johnson Space Center)

Development of a coherent Doppler lidar for precision maneuvering and landing of space vehicles

A coherent Doppler lidar has been developed to address NASA’s need for a high-performance, compact, and cost-effective velocity and altitude sensor onboard its landing vehicles. Future robotic and manned missions to planetary bodies require precise ground-relative velocity vector and altitude data to execute complex descent maneuvers and safe, soft landing at a pre-designated site. This lidar sensor, referred to as a Navigation Doppler Lidar (NDL), meets the required performance of the landing missions while complying with vehicle size, mass, and power constraints. Operating from over five kilometers altitude, the NDL obtains velocity and range precision measurements with 2 cm/sec and 2 meters, respectively, dominated by the vehicle motion. After a series of flight tests onboard helicopters and rocket-powered free-flyer vehicles, the NDL is now being ruggedized for future missions to various destination in the solar system.

10:55 - 11:15

Next-generation-synergetic-observation-system for the unified analysis of CALIPSO, ADM-Aeolus, and EarthCARE-ATLID

Hajime Okamoto (Research Institute for Applied Mechanics, Kyushu University), Kaori Sato (Research Institute for Applied Mechanics, Kyushu University), Shoken Ishii (National Institute of Information and Communications Technology), Makoto Aoki (National Institute of Information and Communications Technology), Tomoaki Nishizawa (National Institute for Environmental Studies), Nobuo Sugimoto (National Institute for Environmental Studies), Yoshitala Jin (National Institute for Environmental Studies), Yuichi Ohno (National Institute of Information and Communications Technology), and Hiroaki Horie (National Institute of Information and Communications Technology)

Next-generation-synergetic-observation-system for the unified analysis of CALIPSO, ADM-Aeolus, and EarthCARE-ATLID

The next-generation-synergetic-ground-based-observation-system is being developed to (1) understand the information content of space borne lidar signals and (2) construct continuous data sets of clouds by using all of these satellites. The ground-based system consists of multiple-field-of-view multiple-scattering polarization lidar, direct- and coherent-Doppler lidars, multi-wavelength high spectral resolution lidar and Doppler cloud radar. CALIPSO lidar has been in operation since 2006. ADM-Aeolus and EarthCARE-ATLID are scheduled to be launched in 2018 and 2020, respectively. In addition, future space-borne coherent Doppler wind lidar is studied in Japan. The new system will offer unique opportunity to fill the gaps in different observation conditions among space-borne lidars. We also discuss the retrieval algorithms of clouds and air motion for the ground-based and space borne systems.

11:15 - 11:35 Coffee Break
11:35 - 13:05

Lasers & Devices II

Chairman : Sammy W. Henderson (Beyond Photonics)

11:35 - 12:00 Invited

Non-mechanical Step and Stare Telescope for Coherent Laser Radar Applications

Steven Serati (Boulder Nonlinear Systems, Inc.), Christopher Hoy (Boulder Nonlinear Systems, Inc.), Douglas Mcknight (Boulder Nonlinear Systems, Inc.), Kelly Kluttz (Boulder Nonlinear Systems, Inc.), Jay Stockley (Boulder Nonlinear Systems, Inc.), Lance Hosting (Boulder Nonlinear Systems, Inc.), and Charley Hale (Beyond Photonics)

Non-mechanical Step and Stare Telescope for Coherent Laser Radar Applications

Step and stare operation is desirable for several laser radar applications, since it allows the sensor system to dwell and collect returns from multiple laser shots, reducing the pulse energy requirements on the laser transmitter. Also, a static look angle through transmit and receive eliminates the need for lag-angle compensation. For most applications, it is also desirable to maximize dwell time and minimize transition time between look angles. For any application, the scanning telescope needs to provide sufficient aperture and scan over the required field of regard. This paper discusses the development of low-mass, low-power, step-and-stare telescopes that use low-voltage, low-frequency electro-optic switching (i.e. no moving parts) to steer a large effective aperture (potentially greater than 15 cm) over wide angles (±45 degrees or larger). Currently, the technology is being integrated into different coherent laser radar systems. Results from these efforts are presented.

12:00 - 12:20

High Power, Uncooled InGaAs Photodiodes with High Quantum Efficiency for 1.2 to 2.2 MicronWavelength Coherent Lidars

Shubhashish Datta (Discovery Semiconductors, Inc.) and Abhay M. Joshi (Discovery Semiconductors, Inc.)

High Power, Uncooled InGaAs Photodiodes with High Quantum Efficiency for 1.2 to 2.2 MicronWavelength Coherent Lidars

Coherent lidars require photodiodes having high quantum efficiency (QE), which operate with a high local oscillator power for shot noise limited detection. We report an uncooled, latticemismatched InGaAs photodiode module for lidars operating at 1.2um to 2.2um wavelength. The photodiode is coupled to a 105um diameter core fiber to maximize its free-space coupling efficiency. The fiber-coupled module exhibits a responsivity of 1.0A/W (80% QE) at 1550nm wavelength and 1.2A/W (73% QE) at 2050nm wavelength. This device demonstrates a linear performance up to a photocurrent of 65mA, and can deliver up to +14dBm of continuous-wave RF output power, i.e. 3.1V peak-to-peak amplitude. Thus, no further RF amplification is needed to maximize the effective number of bits for the backend digitizers. These photodiodes have a -3dB bandwidth of 1.7GHz and are adequate for frequency modulated continuous wave and nanosecond-scale pulsed lidars.

12:20 - 12:45 Invited

History of 1.5µm laser source for the coherent Doppler LIDAR in Mitsubishi Electric.

Takayuki Yanagisawa (Mitsubishi Electric Corporation)

History of 1.5µm laser source for the coherent Doppler LIDAR in Mitsubishi Electric.

We have been developing coherent Doppler LIDARs (CDLs) and its laser sources for 20 years. For pulsed lasers used in CDL, stable single-frequency oscillation, a relatively long pulse width, linearly polarized output, and a high output energy are required. A single-frequency diode-pumped Q-switched Er,Yb:phosphate glass laser with injection-seeding has been used as a laser source in early stage of our CDL. To improve stability of output energy, we applied OPA system using Yb:YAG disk laser and a periodic-poled LiNbO3 in next stage. But it was difficult to realize high stability in the field using a laser oscillator because of its high sensitivity for the temperature and vibration. Therefore we applied a waveguide amplifier using Er,Yb:Glass for CDL. In this paper, we will introduce the history of laser sources and the CDLs in Mitsubishi Electric.

12:45 - 13:05

Development of single-frequency high-energy 2-µm laser for future spacebased coherent DopplerWind Lidar

Shoken Ishii (National Institute of Information and Communications Technology), Atsushi Sato (National Institute of Information and Communications Technology / Tohoku Institute of Technology), Makoto Aoki (National Institute of Information and Communications Technology), Koichi Akahane (National Institute of Information and Communications Technology), Shigeo Nagano (National Institute of Information and Communications Technology), Kohei Mizutani (National Institute of Information and Communications Technology), Satoshi Ochiai (National Institute of Information and Communications Technology), and Minoru Kubota (National Institute of Information and Communications Technology)

Development of single-frequency high-energy 2-µm laser for future spacebased coherent DopplerWind Lidar

Global wind profiling is very important to improve the initial conditions for numerical weather prediction and meteorological studies. A Doppler Wind Lidar (DWL) would be a promising approach for global wind profiling. The National Institute of Information and Communications Technology (NICT) is developing a single-frequency high-energy 2-µm pulse laser, 2-µm key technology and instrument. In the development of a new 2-µm semiconductor laser with quantum-dot structures emits, we found the photoluminescence around at wavelength of 2.03-µm. We demonstrated a Tm-doped fiber amplifier (TDFA) with an amplification of about 20. We developed a high-pulse energy laser emitting 125 mJ at 30 Hz meeting requirements for the future space-based coherent DWL. In the paper, we will report recent progress at NICT.

13:20 - 21:30

Tour and Banquet

Day 4

8:00 - 9:00 Reception and Registration
9:00 - 10:05

Lidars & measurements for wind energy II

Chairman : Yelena L. Pichugina (NOAA)

9:00 - 9:25 Invited

Challenges past, present and future for lidar in wind energy

Michael Harris (ZephIR Lidar)

Challenges past, present and future for lidar in wind energy

Lidar made its first tentative steps in 2003 towards becoming an accepted tool in the wind industry; significant efforts were needed initially to understand the requirements and establish lidar methods. Important questions were raised, including: is lidar reliable and does it work in all conditions, particularly low backscatter? Is the accuracy sufficient? Can costs be reduced? Today, lidar is used onshore, offshore and on the turbine itself for a range of important activities including resource assessment, power performance evaluation, turbine optimisation and active control. The level of acceptance has steadily increased to the point where lidar is now considered mainstream in the growing wind industry, with the development of international standards and roadmaps to bankability. Remaining challenges include better understanding of complex terrain, wakes and turbulence, and greater acceptance by way of certification and standards. In future new applications may emerge as the technology improves with further cost reductions.

9:25 - 9:45

Status of research and development for lidar-assisted wind turbine control in Japan

Yasunari Kamada (Mie University), Hirokazu Kawabata (National Institute of Advanced Industrial Science and Technology), Yutaka Kajiyama (Mitsubishi Electric Corporation), Nobuki Kotake (Mitsubishi Electric Corporation), Tetsuya Kogaki (National Institute of Advanced Industrial Science and Technology), and Takao Maeda (Mie University)

Status of research and development for lidar-assisted wind turbine control in Japan

In recent years, the application of wind lidar has made remarkable progress on the feed-forward wind turbine control and there are some demonstrations on this application to reduce both the turbine loads and yaw misalignment. The researches and developments for this application are now going also in Japan and are introduced here. Mie University and Mitsubishi Electric have demonstrated the power performance stabilization with blade pitch control of Mie University’s test turbine using Mitsubishi Electric’s 9 beam lidar data in their joint research. AIST (National Institute of Advanced Industrial Science and Technology) have tested the same lidar which was installed on the nacelle of their test turbine in their in-house project. In the measurement campaign, they found out the feasibility of increasing energy capture of 6 % by reducing yaw misalignment and also of prediction of incoming extreme gust which contributes to reducing the turbine loads.

9:45 - 10:05

Wind turbine rotor-effective wind speed estimated by nacelle-mounted Doppler wind lidars

Dominique P. Held (Department of Wind Energy, Danish Technical University (DTU), Frederiksborgvej 399, 4000 Roskilde, Denmark / Windar Photonics A/S, Helgeshoj Alle 16-18, 2630 Taastrup, Denmark) and Jakob Mann (Department ofWind Energy, Danish Technical University (DTU), Frederiksborgvej 399, 4000 Roskilde, Denmark)

Wind turbine rotor-effective wind speed estimated by nacelle-mounted Doppler wind lidars

Over the past two decades, research has demonstrated a substantial structural load reduction potential of lidar-assisted wind turbine controllers; especially for lidar-assisted pitch control, opening the possibility of lighter rotors and cheaper wind turbines. Knowing how well a lidar can estimate the rotor-effective wind speed (REWS) is an important aspect of designing an optimal pitch controller. This contribution investigates the inter-comparison between REWS estimated by a forward-looking nacelle-mounted lidar and the wind turbine itself. We present measurements from two experimental campaigns, where an economical and robust cw Doppler wind lidar is mounted on a heavily instrumented Vestas V52 turbine. The results indicate that the coherence between lidar and turbine estimated REWS is in agreement with analytical models. Also, the time delay between the two signals conforms to the expected results. This implies that the models used to design and optimize lidar-assisted pitch controllers match with experimental results.

10:05 - 10:25 Coffee Break
10:25 - 11:35

Measurement, simulation, modeling, and signal processing III

Chairman : Michael Harris (ZephIR Lidar)

10:25 - 10:50 Invited

Collecting large wake vortex data with operational Doppler LIDARs for operational implementing of newWake Turbulence regulations at major airports

Jean-Pierre Cariou (LEOSPHERE, France) and Ludovic Thobois (LEOSPHERE, France)

Collecting large wake vortex data with operational Doppler LIDARs for operational implementing of newWake Turbulence regulations at major airports

For twenty years, coherent Doppler LIDAR systems (CDL) have been used for better understanding wake vortices (WV) behaviors at airports. All these studies helped to design new concepts of wake separations like the RECAT regulation consisting in redefining new WT categories. These new regulations are now under investigation by many airports worldwide in order to validate their operational implementation. A review of the different technologies of CDLs used for wake vortex measurements is performed, as well as a review of the different types of wake vortex (WV) algorithm. The presentation describes in more details one robust, automatic and accurate algorithm based on radial wind speeds designed for collecting large WV data for operational projects. It shows several examples of operational projects at major airports in the world like Paris-Charles de Gaulle airport or Hong Kong airport where wake vortex data collection has been started with CDLs.

10:50 - 11:15 Invited

Characterization of Aircraft Dynamic Wake Vortex and Atmospheric Turbulence by Coherent Doppler Lidar

Songhua Wu (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China / Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology), Xiaochun Zhai (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China), and Bingyi Liu (Ocean Remote Sensing Institute, College of Information Science and Engineering, Ocean University of China / Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology)

Characterization of Aircraft Dynamic Wake Vortex and Atmospheric Turbulence by Coherent Doppler Lidar

This paper gives an overview of aircraft wake vortex observation under near ground effect (NGE) using coherent Doppler lidar (CDL) at Beijing Capital International Airport (BCIA). Two-month outfield experiment from Jan 23 2017 to Mar 22 2017 is introduced. A new method based on the distribution of radial velocity and spectral width from range height indicator (RHI) quick scanning data is then used to capture the wake vortex spatial-temporal evolution process. The circulation of wake vortex is further corrected and calculated using Burnham-Hallock model. The effects of wind and atmospheric turbulence on heavy aircraft wake vortex evolution under NGE are experimentally studied where the dependence of aircraft wake vortex lifespan on the atmospheric conditions are specifically evaluated from the experimental data. Keywords:wake vortex, near ground effect, turbulence, statistics

11:15 - 11:35

Wake vortex measurement using pulsed Doppler lidar

Naoki Matayoshi (Japan Aerospace Exploration Agency), Eiichi Yoshikawa (Japan Aerospace Exploration Agency), and Masayuki Yamamoto (Mitsubishi Space Software)

Wake vortex measurement using pulsed Doppler lidar

The Japan Aerospace Exploration Agency (JAXA) developed the original algorithm to detect wake vortex shed from aircraft using spectral data of pulsed Doppler lidar. The JAXA has conducted the wake vortex measurement at two major airports in Japan using a pulsed Doppler lidar and demonstrated the capability of extracting wake characteristics including wake position and circulation strength from lidar spectral data. The acquired wake characteristics will be used to support safe and efficient aircraft operations. This paper will describe the JAXA’s original wake detection algorithms and observed wake characteristics in detail.

11:35 - 12:55 Lunch Break
12:55 - 14:00

Imaging, acoustic sensing, and novel sensing II

Chairman : Philip Gatt (Lockheed Martin)

12:55 - 13:20 Invited

200-GHz 8-us LFM Optical Waveform Generation for High-Resolution Coherent Imaging

Kevin W. Holman (MIT Lincoln Laboratory, 244 Wood Street, Lexington, MA 02420, USA)

200-GHz 8-us LFM Optical Waveform Generation for High-Resolution Coherent Imaging

Wideband optical waveforms provide high range resolution in coherent imaging applications. When a linear frequency modulated (LFM) waveform is used, stretch processing techniques can be employed that provide range resolution commensurate with the full optical bandwidth of the waveform, with modest receiver electronic bandwidth. However, the waveform must be generated sufficiently rapidly to minimize blurring caused by movement of the scene. In previous work on wideband swept waveform generation, the fastest reported modulation rates were on the order of 1-10 THz/s. Here we report the generation of a 200 GHz waveform with an unprecedented modulation rate of > 24,000 THz/s. We describe our unique scalable approach of modularly generating smaller-bandwidth waveforms across the optical spectrum, and then phase-stitching these sub-components together to form the full-bandwidth 200 GHz waveform in 8 us. We will describe the use of this waveform for diffraction-limited 3D imaging, and sub-diffraction-limited synthetic aperture imaging.

13:20 - 13:40

Sharpness-based correction methods in Far Field Digital Holography

Wesley E. Farriss (Leidos Inc. / The Institute of Optics, University of Rochester), James R. Fienup (The Institute of Optics, University of Rochester), Jason Stafford (Air Force Research Labs, United States Air Force), and David Rabb (Air Force Research Labs, United States Air Force)

Sharpness-based correction methods in Far Field Digital Holography

Anisoplanatism caused by atmospheric turbulence has a deleterious effect on spatial heterodyne images of targets in the far field. One way of correcting these effects is to employ a convex optimization algorithm which improves the overall quality of the image by increasing its sharpness. Typically, these methods utilize discrete phase screen approximations of volumetric turbulence in order to greatly reduce the computational complexity of the problem. However, it is unclear exactly how many phase screens best approximate real volumetric turbulence. Additionally, it is also unclear exactly where these optimization phase screens should be placed to best approximate this turbulence. In this work, we explore the trade space of sharpness-based turbulence mitigation with respect to number, placement, size, and optimization method. Also, the use of algorithmic differentiation in expressing the optimization gradient, in lieu of an explicit gradient, is discussed.

13:40 - 14:00

Various activities in NICT Space-Time Standards Laboratory including optical clocks and applications

Tetsuya Ido (National Institute of Information and Communications Technology)

Various activities in NICT Space-Time Standards Laboratory including optical clocks and applications

Space-Time Standards Laboratory in National Institute of Information and Communications (NICT) has various activities related to time and frequency metrology, including Japan Standard Time and atomic frequency standards. This presentation briefly reviews some research projects related to optical technique, including a chip-scale atomic clock, optical clocks, and a generation of time scale on the basis of a strontium lattice clock. These achievements may help some scientists who requires stable delivery of an accurate frequency standard in a certain level of accuracy.

14:00 - 14:20 Coffee Break
14:20 - 16:25

Ground-based and airborne lidars II

Chairman : Agnes Dolfi-Bouteyre (ONERA), Shoken Ishii (NICT)

14:20 - 14:45 Invited

Fiber-based coherent DIAL/Doppler Lidar at 1645 nm for remote sensing of methane plumes

Nicolas Cezard (Onera, The French Aerospace Lab), Philippe Benoit (Onera, The French Aerospace Lab), Agnes Dolfi-Bouteyre (Onera, The French Aerospace Lab), Didier Goular (Onera, The French Aerospace Lab), Julien Le Gouet (Onera, The French Aerospace Lab), Simon Le Mehaute (Onera, The French Aerospace Lab), Christophe Planchat (Onera, The French Aerospace Lab), Matthieu Valla (Onera, The French Aerospace Lab), and Xavier Watremez (Total, CST-JF)

Fiber-based coherent DIAL/Doppler Lidar at 1645 nm for remote sensing of methane plumes

A new coherent, fiber-based, and dual-function DIAL/Doppler Lidar is currently being developed at Onera, for remote sensing of CH4 plume in case of industrial onshore or offshore gas leaks. The system is designed for operation at 1645 nm in pulsed mode to allow for range-resolved measurements. It relies upon a new fiber laser source developed in the lab. The laser is a semiconductor laser diode amplified and pulsed through a MOFPA architecture using two Raman amplification stages. The lidar emits 10 µJ, 100 ns, linearly polarized pulses at 20 kHz repetition rate from a monomode fiber. The pulse spectral width is 10 MHz, close from the Fourier limit, and is suitable for coherent detection. The frequency stability of emitted pulses is below 100 kHz (<0.1 m/s) for time accumulation over 10 ms. The lidar has been set in monostatic configuration for upcoming wind and CH4 measurements tests.

14:45 - 15:05

Measurement of CO2 mixing ratio profiles using ground based 3-wavelength 1.6 µm CO2-DIAL with temperature measurement techniques in the loweratmosphere

Yasukuni Shibata (Tokyo Metropolitan University), Chikao Nagasawa (Tokyo Metropolitan University), and Makoto Abo (Tokyo Metropolitan University)

Measurement of CO2 mixing ratio profiles using ground based 3-wavelength 1.6 µm CO2-DIAL with temperature measurement techniques in the loweratmosphere

High-accurate vertical carbon dioxide (CO2) profiles are highly desirable in the inverse method to improve quantification and understanding of the global sink and source of CO2, and also global climate change. We have developed a ground based three-wavelength 1.6 µm differential absorption lidar (DIAL) to achieve simultaneously measurements of vertical CO2 concentration and temperature profiles in the atmosphere. The high accuracy of absorption cross sections with temperature dependence is achieved by this three-wavelength DIAL. The three-wavelength DIAL system is constructed from the optical parametric generator and the direct detection receiving system that included a near-infrared photomultiplier tube operating at analog mode. In this paper, some experimental measurement results of temperature profiles and CO2 mixing ratio profiles are reported from 0.4 to 2.5 km altitude.

15:05 - 15:25

Investigations on the performance of lidar measurements with different pulse shapes using a multi-channel Doppler lidar system

Albert Tows (Cologne University of Applied Science) and Alfred Kurtz (Cologne University of Applied Science)

Investigations on the performance of lidar measurements with different pulse shapes using a multi-channel Doppler lidar system

We present an all-fiber multi-channel coherent Doppler lidar system to measure wind velocities with different pulse parameters. Full automatic feedback control of pulse shapes and durations on each wavelength-channel allows this system to send laser pulses with individual pulse parameters into the atmosphere simultaneously. This is realized by changing the seed pulse shape for each channel before amplification with a fiber amplifier chain. The shaping unit and technique are presented and the influence of different pulse shapes and durations on the lidar performance in terms of the resulting signal-to-noise ratio, Doppler spectrum width, velocity precision, and range gate weighting function in atmospheric measurements is investigated. A comparison of two main transmitted pulse shapes will be discussed: a Gaus- and square-shaped pulse.

15:25 - 15:45

Validation of airborne 1.5µm all-fiber coherent lidar measurement of wind profiles

Xiaopeng Zhu (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), Jiqiao Liu (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), Xin Zhang (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), Yuan Liu (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), Xiaolei Zhu (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences), and Weibiao Chen (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences)

Validation of airborne 1.5µm all-fiber coherent lidar measurement of wind profiles

A high pulse energy 1.5 µm all-fiber coherent Doppler lidar airborne engineering prototype is developed for wind profiles measurement. The lidar system is very compact with 300 µJ single pulse energy output and 100 mm telescope diameter, which could work in wide temperature range . Wind profiles are measured every 16 seconds with 60m range resolution. The airborne wind profiles measurement experiments based UAV platform were successfully implemented. The airborne lidar measured wind speeds were compared with the ground-based coherent wind lidar and the GPS balloon, and good agreements were validated with wind speed standard error of less than 1 m/s from 1700 m to 3700 m.

15:45 - 16:05

From Windcube#0001 to Windcube#1000 : Doppler Lidar as a mature technology.

Jean-Pierre Cariou (LEOSPHERE, France), Ludovic Thobois (LEOSPHERE, France), and Peter Spencer (LEOSPHERE, France)

From Windcube#0001 to Windcube#1000 : Doppler Lidar as a mature technology.

10 years after the Windcube #0001, Leosphere has delivered its 1000th Windcube Doppler Lidar. Still based on the pulsed fibered technology at 1.5µm, the Windcube is now an industrial product widely used for Wind Ressource Assessment and Weather Monitoring. Tracing the path of technological progress from laboratory to industry in hardware and software, but also the progress in metrology, the presentation expresses the various and demanding application requirements, the continuous improvements of coherent lidar solutions and the slow but inexorable acceptance of remote sensors in wind energy and meteo applications.

16:05 - 16:25

Mobile coherent doppler lidar prototype v2 for wind sensing

Toshiyuki Ando (Mitsubishi Electric Corporation)

Mobile coherent doppler lidar prototype v2 for wind sensing

We have developed ultra-compact coherent doppler lidar prototype version 2 for wind sensing. This new mobile lidar has its dimension of 39x29x16 cm, its weight of 2.9kg, and power consumption of 35W. The new mobile lidar can be operated by a lithium battery and can be continuously measured wind profile over 2.5 hours, thanks to the low consumption optical tranceiver / signal processor sub system, called coherent doppler lidar engine. Preliminary experiments have been perfomed by this mobile lidar prototype 2 for line of sight wind velocities with the maximum horizontal range more than 1km.

16:25 - 16:40

Conclusion and Remarks

Keynote Speaker

Robert L. Byer

(Stanford University, USA)

Biography

Professor Robert L. Byer is the William R. Kenan, Jr. Professor of Applied Physics at Stanford University.He has conducted research and taught classes in lasers and nonlinear optics at Stanford University since 1969.He has made numerous contributions to laser science and technology including the demonstration of the first tunable visible parametric oscillator, the development of the Q-switched unstable resonator Nd:YAG laser, remote sensing using tunable infrared sources and precision spectroscopy using Coherent Anti Stokes Raman Scattering (CARS).Current research solid state laser sources with applications to gravitational wave detection and to laser particle acceleration.

Professor Byer is a Fellow of The Optical Society, the Institute of Electrical and Electronics Engineers (IEEE), the American Physical Society and the American Association for the Advancement of Science and the Laser Institute of America.In 1985 Professor Byer served as president of the IEEE Lasers and Electro-optics Society. He was elected President of the Optical Society of America in 1994. He served as President of the American Physical Society in 2012.

Special Speaker

Kazuhiro Asai

(Tohoku Institute of Technology, Japan)

Biography

Professor. Kazuhiro Asai was born in Aichi in 1946.He graduated from Tokyo Denki University in 1968 and served as a research associate at Research Institute of Electrical Communication, Tohoku University (Sendai, Miyagi) during 4 years from 1969 to 1973. He received a Doctor of Engineering degree in research on “Spectroscopic studies of Tropospheric Ozone and it's Remote Detection using Infrared Laser Differential Absorption” from Tohoku University in 1978. He worked at the former Radio Research Laboratory (the current National Institute of Information and Communications Technology (NICT)) for 12 years, and then moved to Tohoku Institute of Technology (Sendai, Miyagi) as a professor in 1989. He became a professor emeritus in 2012. In 1984 and 1985, he also served as a postdoc at Georgia Institute of Technology in Atlanta, Georgia. His major research fields are DPSS cw/Q-switched lasers, and it's applications for remote sensing. He has served a member of Advisory Board of CLRC since 2003 and was a conference chair at 13th CLRC held in 2005 in Kamakura, Japan. He has served as a visiting researcher at the former National Space Development Agency (the present Japan Aerospace Exploration Agency (JAXA) during eleven years from 1990 to 2000 for conducting the first space-based lidar (ELISE : Experimental Lidar In Space Environment) program.

He is now involved two lidar programs in JAXA, “MOLI” and “SafeAvio”. The former is a vegetation lidar program named “Multi footprint Observation Lidar and Imager (MOLI)” for measuring global forest canopy height from the International Space Station (ISS)-Japanese Experiment Module (JEM). It is planned to be launched in 2021. The latter is an airborne coherent Doppler lidar (CDL) program called “SafeAvio” for establishing warning system for wake vortex, mountain wave or clear air turbulence.

Invited Speakers

1. Photonics Integrated Circuit Lidars

Paul J. M. Suni (Lockheed Martin Coherent Technologies Inc., USA)
Stephen C. Crouch (Blackmore Sensors and Analytics Inc., USA )

2. Imaging, Acoustic Sensing, and Novel Sensing

Kaoru Minoshima (The University of Electro-Communications, Japan)
Kevin W. Holman (Massachusetts Institute of Technology, USA )

3. Lasers & Devices

Jirong Yu (National Aeronautics and Space Administration, USA)
Takayuki Yanagisawa (Mitsubishi Electric Corporation, Japan)
Steven A. Serati (Boulder Nonlinear Systems, USA)
Atsushi Sato (Tohoku Institute of Technology, Japan)

4. Ground-based and Airborne Lidars

Stephan Rahm (Deutsches Zentrum fur Luft- und Raumfahrt, Germany)
Nicolas Cezard ( Office National d'Etudes et de Recherches Aerospatiales, France)
Shigeru Machida (Japan Aerospace eXploration Agency, Japan)

5. Space-based Lidars

Alain M. Dabas (Meteo-France, France)
Benjamin Witschas (Deutsches Zentrum fur Luft- und Raumfahrt, Germany)
Upendra N. Singh (National Aeronautics and Space Administration, USA)

6. Lidars and Measurements for Wind Energy

Michael Harris (ZephIR Lidar, UK)
Mikael Sjoholm (Technical University of Denmark, Denmark)
Yelena L. Pichugina (National Oceanic and Atmospheric Administration, USA)
Jean-Pierre Cariou (Leosphere Societe par Action Simplifie, France)

7. Measurement, Simulation, Modeling, and Signal Processing

Songhua Wu (Ocean University of China, China)
Mark J. Campmier (CUNY City College of New York, USA)