星载激光相干测高计的参量设计

为使星载激光高度计实现高空间分辨力、高距离精度,提出了联合采用调频光纤激光器和相干测距的方法。详细讨论了这种方法的实现方案,并对方案中的激光发射功率、望远镜口径以及脉冲宽度对距离精度及信噪比的影响进行数值模拟。对系统参量进行分析,得到了相关参量的关系和优化的参量。结果表明,当望远镜口径为400 mm时,啁啾调频速率为1 MHz/μs,脉冲时间宽度150~350μs,发射功率10 W左右时,基于相干测距的星载激光高度计可以实现距离精度小于15 cm的技术指标。

In order to realize the high spatial and range resolution for a space-borne laser altimeter based on frequency-modulated fiber laser and heterodyne-range detection is proposed. The detailed principle of detection is presented. The relationship of range accuracy and signal-to-noise ratio with laser power, telescope diameter, and pulse width are numerically simulated. The relationship and the optimized parameters are given after the analysis of system parameters. The results show that the space-borne laser altimeter based on coherent range detection can achieve a range accuracy of less than 15 cm with telescope aperture of 400 mm, chirp rate of 1 MHz/μs. pulse width ranges of 150-350 μs, and average laser power of about 10 W.