一种新的大斜视TOPS SAR全孔径成像方法

针对大斜视模式导致回波信号距离向和方位向耦合严重,循序扫描地形观测模式波束指向的变化导致全孔径回波信号的方位带宽大于系统脉冲重复频率,引起方位谱模糊的问题,提出了一种基于修正距离徙动算法和方位谱分析的全孔径成像算法.对于全孔径数据,首先通过方位预处理获取信号无模糊的二维频谱,然后采用修正距离徙动算法进行距离徙动校正,最后通过谱分析技术和方位去斜技术将信号聚焦在方位频域.仿真实验和实测数据结果验证了该算法的有效性.

Novel full aperture imaging algorithm for highly squinted TOPS SAR

Due to its special imaging geometry, the highly squinted Terrain Observation by Progressive Scans (TOPS) SAR imaging mode is confronted with two main issues: severe range-azimuth coupling caused by high squint angles and azimuth spectrum aliasing caused by the steered azimuth beam. To solve these issues, a full aperture imaging algorithm based on the modified range migration algorithm (RMA) and spectral analysis (SPECAN) is proposed in this paper. Firstly, the two-dimensional (2-D) spectrum without aliasing is obtained by azimuth preprocessing. Then the modified RMA is used to complete range cell migration correction (RCMC) and range compression. Finally, the signal is focused in the Doppler domain by SPECAN and Deramping. Simulations and real data processing results validate the effectiveness of the proposed algorithm.