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

1. Validation of airborne 1.5 μm all-fiber coherent lidar measurement of wind profiles Jiqiao Liu,Xiaopeng Zhu,Xin Zhang, Xiaolei Zhu,Weibiao Chen , Shanghai Institute of Optics & Fine Mechanics (SIOM), Chinese Academy of Sciences

2. Outline Motivation Airborne coherent lidar development Experiment results Summary

3. 1. Motivation • In lower atmospheric troposphere, coherent Doppler lidar shows more advantages: • High accuracy • High spatial and temporal resolution • High sensitivity and insensitive to solar background • A compact coherent lidar is required to measure wind profiles to almost 3 km altitude. • The lidar can meet airborne platform condition. All-fiber pulsed coherent lidar is the best choice!

4. 2. Airborne coherent lidar development 1.5 µm Fiber laser is selected • high efficiency • robust and low weight • fiber components and detector maturity • Lidar consists of three parts: • High Power fiber laser • Telescope and scanner • Detector Electronics and Power supply • Power supply≤600W

5. Wind vector measurement LOS wind profile Scanning Multiple LOS • VAD combined Wind vector （Horizontal wind speed, direction and vertical wind speed）

6. Coherent wind lidar on airborne platform VAD scanning: 8 azimuth LOS within 15s LOS wind speed of VAD scanning • 100mm Lens scanner • 20° deflection angle • Position ,attitude and velocity are measured from GPS/INS

7. Airborne wind speeds retrieval LOS wind speeds correction in airborne platform • Wind speeds vector retrieval-nonlinear fit equation

8. 1.5μmall-fiber single frequency laser configuration • Seeder laser+modulater+MOPA(amplifier)

9. 1.5μmall-fiber single frequency laser source High energy source of 500 μJ 470ns ＞500μJ OSNR>30dB M2:1.10/1.17

10. Developed airborne coherent Doppler lidar 2017,1.5μm, 35kg （Airborne prototype II） 2015,1.5μm, 45kg （Airborne prototype I） UAV platform Harsh environment endurance : • Wide operation temperature range: -40℃-+55℃ • Shock: 20g (@10ms)/ Sine vibration: 2g

11. 3. Experiment results Airborne campaign I in Weihai, Shandong (2015) • Airborne campaign II in Huayin, Shanxi (2017) (UAV platform)

12. Airborne campaign in Weihai, Shandong Wind lidar GPS/INS Jan.7-19, 2015 Successful validation for Airborne coherent wind lidar

13. Airborne campaign in Weihai, Shandong Flight track Altitude:2km Ground validation instruments：Balloon +Ground-based wind lidar

14. Airborne campaign in Weihai, Shandong Horizontal wind speeds Ocean Land/Ocean • Horizontal wind directions

15. Airborne campaign in Weihai, Shandong Wind speeds comparison -Airborne wind lidar、Balloon and Ground based wind lidar • Airborne VS Balloon • Airborne VS Balloon • Airborne VS Ground • Airborne VS Ground

16. Airborne campaign in Huayin, Shanxi Preliminary experiment on Mar.29, 2017 UAV Flight altitude:3~4km Close to Huashan Mountain • Ground Validationinstruments • GPS Balloon • Ground-based wind lidar (Airborne prototype I) Flight trace Ground wind Lidar Mountain height >1600m GPS balloon & Drift path Mountain height >1700m

17. UAV platform altitude and attitude during flight Pitch Flight altitude Climb Climb cruise Roll Yaw

18. Airborne campaign in Huayin, Shanxi Horizontal wind speeds • Horizontal wind directions

19. Airborne campaign in Huayin, Shanxi • Vertical wind speeds • Relative signal amplitude -Jan.19,2015 • Range corrected signal Cloud

20. Airborne campaign in Huayin, Shanxi Wind speeds and directions comparisons - Airborne wind lidar、Balloon and Ground based wind lidar 1700m~3700m • Airborne VS Balloon • Airborne VS Balloon • Balloon VS Ground • Balloon VS Ground

21. Summary The compact airborne coherent wind lidar prototypes with high pulse energy are developed. Airborne campaign experiments are implemented successfully to validate the performance. Further UAV experiments are scheduled in 2018. The airborne wind lidar could also be acted as validation instrument in China for ALADIN wind lidar in future.

22. Thanks for your attention！