Verification of all-fiber airborne coherent Doppler lidar for airspeed sensing and wind measurement

Coherent Doppler Lidar (CDL) has garnered significant attention for its remote sensing capabilities and high accuracy, establishing it as a pivotal technology in environmental monitoring. The dynamics of airborne platforms are intricately linked to wind conditions, making airborne CDL a crucial tool for enhancing aviation safety. Additionally, airborne CDL systems provide comprehensive meteorological data across extensive geographical areas. We introduce an all-fiber continuous-wave (CW) CDL system specifically engineered for integration with flight instrumentation. This CDL system excels in measuring and reconstructing critical flight parameters such as true airspeed (TAS), angle of attack (AoA), and sideslip angle (AoS). A key feature of the CW CDL system is providing three-dimensional airspeed measurements at a data rate of 50 Hz, capturing data from a position 30 meters ahead of the aircraft. To ensure the accuracy and reliability, a series of verification experiments were conducted. Initially, ground-based comparison experiments were performed using a wind tunnel, a wind tower, and a vehicle-mounted sonic anemometer. For airborne verification, the lidar was installed on an aircraft. The aircraft flew at three different indicated airspeeds and four different altitudes, enabling a comprehensive comparison between flight instrument speed data and the results obtained from the CW CDL system. The linear analysis of these airborne experiments consistently yielded correlation coefficients exceeding 0.97, with the mean deviation of less than 1 m/s.