针对星载合成孔径雷达(SAR)方位高分辨与宽测绘带之间的矛盾,提出脉内聚束SAR模式实现高分辨宽测绘带成像.建立了脉内聚束SAR模型,分析了脉内聚束SAR回波信号特性,得出脉内扫描技术会导致不同方位子场景上散射点相互叠加引起距离模糊的结论.针对该距离模糊,利用俯仰维多孔径进行空域滤波解模糊;并分析了地形起伏对成像结果的影响.脉内聚束SAR利用脉内扫描获得更长的合成孔径,以此实现高的方位分辨率;同时在采用低脉冲重复频率的情况下,获得宽测绘带,从而实现了高分辨宽测绘带成像.仿真实验结果验证了该方法的有效性.
With respect to the contradiction between high resolution and wide swath,the intrapulse spotlight synthetic aperture radar(SAR) mode is presented to achieve high azimuth resolution wide swath imaging.Firstly,the model of intrapulse spotlight SAR is established,and then the characteristic of echoes in this mode is analyzed in detail.The conclusion that the intrapulse scanning can make scatterers in the different azimuth sub-scene ambiguous are given.The degrees of freedom along the elevation direction are used to resolve the range ambiguities.Meanwhile we analyze the impact of the fluctuating terrain on the imaging result.In the intrapulse spotlight SAR mode,the long synthetic aperture acquired by the intrapulse scanning technique can realize the high azimuth resolution.Meanwhile a low pulse repetition frequency(PRF) is adopted to achieve a wide swath.Therefore high azimuth resolution wide swath imaging can be achieved by intrapulse spotlight SAR mode.Results of simulation show the effectiveness of this method.