双基星载HRWS-SAR系统俯仰向DBF处理技术

摘要

In bistatic spaceborne High Resolution Wide Swath SAR (HRWS-SAR) system, the Digital Beam Forming (DBF) technique is employed to achieve the coherent combination of multi-channel signals in the fast time domain, and its performance is affected by the bistatic configuration. For a point target, the relationship between receiver aspect angle and the sum of transmitter distance and receiver distance is approximated by a linear function, and the echo signal model in elevation channel is built. Further, a DBF processing scheme is proposed, which combines the time-variant weighting and Finite Impulse Response (FIR) filtering, and the implementation block diagram is presented. The DBF processing is simulated in several typical bistatic configuration spaceborne HRWS-SAR systems. Simulation results show that the higher DBF performance can be achieved in the spaceborne HRWS-SAR system with rational bistatic configuration.%双基星载高分辨率宽测绘带SAR系统(HRWS-SAR)利用数字波束形成技术(DBF)将俯仰向多通道的回波信号进行快时间域的相干合成,DBF处理性能必然受到双基构型的影响.该文针对一般双基构型的星载HRWS-SAR系统,推导了点目标接收方向角与收发距离和之间的线性近似表达式,建立了俯仰向通道的回波信号模型,进而构建了一种时变加权与FIR滤波相结合的DBF处理方法,并给出了系统实现框图.该文对几种典型双基构型的星载HRWS-SAR系统DBF处理进行了仿真,结果表明合理的双基构型能有效提升星载HRWS-SAR系统的DBF处理性能.