面向星载SAR系统的星间地形散射干扰研究

Research on mutual terrain scattered interference for spaceborne SAR system

射频干扰是影响星载SAR系统精细化观测能力的主要因素,而随着组网卫星的发展,在星载SAR系统时空频交叠的情况下,又出现了一种新的地形散射干扰。因此,研究星载SAR系统的星间地形散射干扰对于提高其观测能力具有重要意义。本文介绍了星载SAR系统的星间地形散射干扰样式,分析了其存在条件和作用机理,构建了干扰传播路径的几何关系,推导出叠加干扰后的回波信号模型。基于地面直射干扰和星间散射互扰信号模型的不同,对比分析了两种干扰在不同信号表征域中的特征差异。仿真分析了模拟场景下不同干扰源所产生的成像结果,并从成像质量评估方面给出了雷达工作带宽、脉冲重复频率和卫星运行速度的影响。

Radio frequency interference(RFI) is a main factor that affects the fine observation ability of spaceborne synthetic aperture radar(SAR) systems.With the development of networking satellites,a new terrain scattered interference(TSI) has appeared in the case of overlapping of time,space,and frequency between spaceborne SAR system.Therefore,it is of great significance to study the mutual terrain scattered interference(MTSI) of spaceborne SAR systems for improving their observation ability.In this paper,the pattern,existing conditions,and mechanism of MTSI were introduced.Then,the geometric relationship of the interference propagation path and the echo signal model after superposition interference was acquired.Based on the different signal models of ground direct interference and MTSI,the characteristic differences between the two kinds of interference in different signal representation domains were compared and analyzed.Finally,the imaging results produced by different interference sources in the simulated scene were simulated and analyzed,and the influence of bandwidth,pulse repetition frequency,and satellite velocity were given from the aspect of imaging quality evaluation.