小卫星分布式SAR系统的信噪比研究

The Analysis of SNR in Passive Distributed Microsatellites SAR System

小卫星分布式合成孔径雷达(SAR)系统可以提高成像分辨率,检测地面运动目标和进行数字高程测量。但由于小卫星接收天线面积的减小使其输入信噪比相对于主星大大降低,这将严重影响系统的性能。该文以JERS-1为主星,分析了小卫星分布式SAR系统的信噪比以及信噪比降低对成像、测高、检测动目标等的影响。分析表明此系统的信噪比将不能满足系统对信噪比的最低需求。最后讨论了用相干或非相干处理来改善系统输出信噪比的方法。

The passive distributed microsatellites Synthetic Aperture Radar（SAR） system has the capabilities in improving image resolution, detecting ground moving targets and computing digital elevation models. But the input Signal-to-Noise Ratio （SNR） of the system will largely reduce compared with the active spaceborne radar because of the decrease of its receiving antenna＇s area, which will degrade the performance of the system. This paper analyses the effect of the SNR＇s reduction on SAR imagery, Digital Elevation Model （DEM） and Ground Moving Target Indication （GMTI）, based on the JERS-1 acted as the active satellite, and comes to a conclusion that the SNR obtained from the system would be lower than what the system required. Some methods to improve the system＇s output SNR by coherent or noncoherent operating are also discussed.