基于压缩感知的宽测绘带海面运动目标多普勒补偿成像算法

An Effective Doppler Compensation Approach Based on Compressed Sensing for the Wide-Swath Oceanic Moving Target SAR Imaging

针对宽测绘带海面运动目标成像过程中存在距离模糊问题,利用了不同脉冲时刻发射正交编码信号,同时利用了压缩感知技术进行解距离模糊。由于正交编码对海面目标的运动特性比较敏感,编码信号的脉内多普勒特性将影响距离模糊的求解性能。对编码信号的脉内多普勒特性进行推导与分析,得到脉内多普勒特性体现为距离快时间的频移且该频移量等于方位慢时间的多普勒频率。因此,提出了在回波信号的距离时域方位多普勒域进行编码信号的脉内多普勒特性补偿算法,通过仿真试验分析证实所提出方法的有效性。

The range ambiguous is un-avoid for the wide-swath oceanic moving target SAR imaging with low pulse repetition frequency.In this paper,the orthogonal coded signal is transmitted at different pulse times and the compressed sensing approach is employed to solve the problem of range ambiguous.Since the orthogonal coded signal is highly sensitive to the motion characteristics,the performance of range ambiguous suppression is deteriorated by the continuous motion of radar platform and imaging target.In this paper,the Doppler characteristics of transmitted signal are deduced and analyzed.For the transmitted coded signal,a conclusion is obtained that the influence brought by the motion is equivalent to the frequency shift in the range fast time domain.In addition,the frequency shift equals to the azimuth Doppler frequency,which is corresponding to azimuth slow time.Then,an effective Doppler compensation approach is proposed,where the inter-pulse Doppler compensation is implemented in the range time and azimuth Doppler domain for the orthogonal coded signal.Finally,some simulation experiments are conducted to verify our proposal.