合成孔径激光雷达光学系统和作用距离分析

摘要

Optical system and detection range of Synthetic Aperture Ladar (SAL) are analyzed. According to the imaging characteristics of SAL, the concept that SAL uses non-imaging diffractive optical system are proposed, meanwhile, the phased array model is introduced to analyze its performance. In the condition of using binary optical element on the feeder and primary mirror, the phaser parameters and beam pattern are presented using simulation. The signal of 2° view field is introduced into fiber with the 300 mm aperture telescope and compressed optical path. The radar detection range equation of SAL is introduced, coherent detection and signal accumulation gain are analyzed, the conclusion is SAL has good ability of detecting weak signal. Aiming at application requirement, system parameters and working modes of airborne SAL are given with high resolution and long detection range. With 5 cm resolution, the airborne SAL can achieve 5 km detection range with 1.5 km swath in strip-map imaging mode and 10 km detection range with 1 km swath in sliding spotlight imaging mode.%该文对合成孔径激光雷达(Synthetic Aperture Ladar, SAL)光学系统和作用距离进行了分析.根据SAL成像特点,提出了SAL使用非成像衍射光学系统的概念,并引入相控阵模型对其性能进行分析.通过在压缩光路中馈源和主镜两处使用二元光学器件,在口径300 mm条件下将2°接收视场信号收入光纤,对所需的相位参数和对应的波束方向图进行了计算仿真.给出了SAL作用距离方程,分析了相干探测和信号积累增益,明确了SAL具有良好的微弱信号探测能力的结论.针对实际应用需求,给出了一个远距离高分辨率机载SAL系统参数和工作模式.5 cm分辨率时,在连续条带成像模式下,其作用距离可达5 km,幅宽可达1.5 km;在滑动聚束成像模式下,作用距离可达10 km,幅宽可达1 km.