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SAR DPCMAB(方位向多相位中心多波速模式)能够提高方位向采样率,同时却带来非均匀采样的问题,通过频谱重构算法能够有效的恢复原信号频谱。但是在SAR传感器运行过程中存在通道特性不一致,采样时刻偏差,噪声等干扰因素,导致重构后的信号出现频谱噪声,重构精度收到影响。研究一种基于方位向相位中心偏移天线技术的机载SAR实现方法。通过在方位向上安置相位中心偏移的多个波束来降低系统对脉冲重复频率的要求,从而在保证方位向分辨率不变的条件下能够扩展机载SAR的测绘带宽。针对由PRF的变化造成的方位信号非均匀采样,采用多通道重构算法来恢复均匀采样信号。并以两通道机载SAR为例,通过仿真实例验证该算法的有效性。
SAR DPCMAB (azimuth polyphase center multi-wave speed mode) can improve the azimuth sampling rate, meanwhile bring about the problem of non-uniform sampling. Spectrum reconstruction algorithm can effectively recover the original signal spectrum. However, during the operation of the SAR sensor, there are some interference factors such as inconsistent channel characteristics, sampling instants, and noise, resulting in spectral noise in the reconstructed signal, which affects the reconstruction accuracy. A method of airborne SAR based on azimuth phase center offset antenna technology is studied. The system reduces the repetition rate of the pulse by placing multiple beams shifted in the azimuth direction up to the center of the phase so as to expand the mapping bandwidth of the airborne SAR without changing the azimuth resolution. For the non-uniform azimuth signal caused by the change of PRF, a multi-channel reconstruction algorithm is used to recover the uniformly sampled signal. Taking the two-channel airborne SAR as an example, the validity of this algorithm is verified by simulation examples.