多发多收SAR编码正交信号设计及性能分析

Design and performance analysis of orthogonal coding signal in MIMO-SAR

多发多收(MIMO)雷达是一种新的雷达体制,具有许多突出的优点.将MIMO技术应用于对地观测的SAR系统,将为高性能地完成高分辨率、宽测绘带成像和GMTI等功能提供有效途径.正交波形优化设计是MIMO雷达研究中的基础性关键问题.首先针对SAR应用的特点,考虑同频编码正交信号之间互相关能量影响,提出了综合积分旁瓣比指标定义.然后通过理论分析和一维数值仿真论证了同频编码正交信号综合积分旁瓣比性能无法满足SAR成像的要求;再通过数值仿真验证了失配滤波处理仍然无法改善同频编码正交信号的综合积分旁瓣比性能.最后优化设计了一组相位编码正交信号作为MIMO-SAR发射信号,通过MIMO-SAR成像和InSAR仿真试验,进一步验证了分析结论的有效性.

Multi-input multi-output（MIMO） radar which has evident advantages in many applications is a new radar system.Applying the MIMO technique to the earth observing synthetic aperture radar（SAR） system offers effective ways for the improvement of high resolution and wide swath imaging and ground moving target indication（GMTI） systems.Designing the optimal orthogonal waveform is a crucial problem in the research on MIMO radar.First,the index definition of synthetic integrated side-lobe level ratio（ISLR） is proposed by focusing on the SAR application and considering the cross-correlation energy influences between orthogonal coding signals with the same frequency band.Second,it is theoretically demonstrated that the performance of synthetic ISLR of orthogonal coding signals with the same frequency band cannot meet the demands of SAR imaging,which has been proved by one-dimensional numerical simulation.Third,it has been shown through numerical simulation that the performance of synthetic ISLR of orthogonal coding signals still cannot be improved by dealing with the mismatched filtering.Finally,a set of orthogonal phase coding signals are designed for multiple MIMO-SAR antennas.The conclusions are verified through MIMO-SAR imaging and InSAR simulation experiments.