微小卫星雷达隐身性能的在轨逆合成孔径雷达成像分析

摘要

成像雷达是空间目标监视系统中的重要组成部分.为深入评估某微小卫星的隐身性能,对卫星的逆合成孔径雷达(ISAR)成像效果进行预测,从雷达成像角度评估卫星的隐身效果.首先简述用于空间目标成像的ISAR成像的基本原理.然后构造卫星的散射点模型,散射系数采用微波暗室的实际测量值.依据仿真雷达系统参数和卫星实际在轨运行参数,计算卫星ISAR成像所需成像时间.对卫星3种飞行姿态,即卫星顶部指向地球表面的隐身姿态、卫星顶部与飞行方向一致和卫星底部指向地球表面两种非隐身姿态,以及不同信噪比情况,进行ISAR仿真,详细分析每种情况下的运动补偿效果和最终ISAR成像效果,说明了卫星隐身设计的有效性.%Imaging radar is an essential part of space surveillance system. The radar-stealth performance of a minisatellite is evaluated and verified from the perspective of radar imaging. Firstly, the principle of inverse synthetic aperture radar (ISAR) imaging is introduced, which is widely used in space object imaging. Then, a multi-scattering model is constructed with proper RCS obtained by practical testing in microwave dark room for the later numerical imaging simulation. Integration time required by the imaging is estimated from the simulated radar system parameters and trajectory parameters of the satellite. Imaging simulation is performed under three scenarios with different SNR levels; (1) The satellite top points to the earth surface, which is referred to as the stealth attitude; (2) The orientation of the satellite top is the same with the satellite flying direction; (3) The satellite bottom points to the earth surface. The effects of motion compensation and the reconstructed image under these scenarios are analyzed and compared, results show that the stealth design of minisatellite is effective.