基于直达波补偿的星地双站SAR滑动聚束模式频域成像算法

星地双站合成孔径雷达以星载系统为机会照射源，地面接收机接收直达波和散射波信号进行同步和成像处理。本文介绍了星地双站SAR系统结构，对基于直达波进行距离向脉冲压缩后的信号调频率、距离徙动以及二维频谱的空变性进行了分析。在此基础上，基于方位向预处理过程、直达波补偿以及非线性Chirp Scaling算法，提出了适合该模型的频域成像算法，并通过点目标仿真验证了该成像算法的有效性和性能。星地双站SAR实测数据进一步验证了该成像算法的有效性。

Processing the Sliding Spotlight Bistatic SAR Based on Direct-Path Signal Compensation

In fixed-receiver bistatic synthetic aperture radar (SAR), the spaceborne SAR was used as the illuminator. Taking account into the high signal-to-noise ratio (SNR) advantage, the direct-path signal is used as reference signal for range match filtering. Then the range compression can be realized with time and frequency synchronization process. However, after range compression, the range history of point target consists of three square-root terms which is hardly to use the Principle of Stationary Phase (POSP). Based on azimuth preprocessing, direct-path signal compensation and nonlinear Chirp Scaling imaging algorithm, a new focusing algorithm is presented in this paper. Simulation results of point targets are presented to validate the feasibility and efficiency of the proposed method. Finally, this algorithm was also validated by the measured data of the HITCHHIKER system.