微振动对星载傅里叶变换光谱仪的影响分析

Influence of Micro-vibration on Space-borne Fourier Transform Spectrometer

文章介绍了一种利用星载傅里叶光谱仪(FTS)进行大气成份探测方法。该光谱仪基于动镜干涉原理,采用空心角镜摆臂扫描、计量激光进行触发的采样方式,实现光谱探测。这种设计尽可能的减轻了FTS在采样过程中卫星平台的振动对干涉效果和光谱数据的影响。文章首先介绍了星载傅里叶变换光谱仪的在轨工作模式、系统组成和干涉模块的光学方案,给出了微振动对傅里叶光谱仪干涉信号和光谱信号影响的数学模型,针对卫星平台微振动的频率和振幅特性,开展了典型工况条件下干涉信号和光谱信号的仿真计算。仿真结果显示随着振动量级增大,光谱图上的鬼线幅值明显增大;另外,延迟匹配精度对探测精度具有重要影响,延迟匹配误差越大,产生的鬼线幅值越大。分析表明,在小于卫星平台的微振动幅度(30×10-3gn)时,微振动对星载傅里叶变换光谱仪的影响可以控制在可接受范围内。

This paper introduces an approach to detecting the composition of atmosphere by using space-borne Fourier Transform Spectrometer （FTS）, and presents the working principle and system constitution The FTS is based on Michelson interferometer. A rotating arm carrying a pair of cube comer retro-reflectors is used to produce optical path difference （OPD）, and an interferogram of metrology laser is used to trigger the equal OPD interval data acquisition. It is well known that FTS is highly sensitive to micro-vibration distur- bances. However, a wide variety of mechanical disturbances are present as the satellite is in orbit. For this end, this paper investigates the influence of micro-vibration on the space-borne FTS. A theoretical model is firstly derived. Then, according to the characteristic of dynamic environment in orbit, the variation of spectra in re- sponse to micro-vibration levels is simulated. The results show that the amplitudes of ghost lines in spectra in- crease rapidly with the increasing of micro-vibration level. In addition, the time delay mismatch has significant impact on the spectra, the amplitudes of ghost lines in spectra increase with the increasing of time delay mis- match. The analysis indicates that the influence of micro-vibration on space-borne FTS is allowable when the micro-vibration level is below 30×10^-3gn.