Xu Wei, Lu Xuhang, Huang Pingping, Tan Weixian, Gao Zhiqi, Qi Yaolong
College of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, China.
Inner Mongolia Key Laboratory of Radar Technology and Application, Hohhot 010051, China.
Sensors (Basel). 2023 Oct 10;23(20):8377. doi: 10.3390/s23208377.
Conventional squinted sliding spotlight synthetic aperture radar (SAR) imaging suffers from substantial swath width reduction and complex processing requirements due to the continuous variation in the squint angle and the large range cell migration (RCM) throughout the data acquisition interval. A novel two-dimensional (2D) beam scanning mode for high-resolution wide swath (HRWS) imaging is proposed. The key to the novel imaging mode lies in the synchronous scanning of azimuth and range beams, allowing for a broader and more flexible imaging swath with a high geometric resolution. Azimuth beam scanning from fore to aft was used to improve the azimuth resolution, while range beam scanning was adopted to illuminate the oblique wide swath to avoid the large RCM and the serious swath width reduction. Compared with the conventional sliding spotlight mode, both the swath width and swath length could be extended. According to the echo model of this imaging mode, an echo signal preprocessing approach is proposed. The key points of this approach are range data extension and azimuth data upsampling. A designed system example with a resolution of 0.5 m, swath width of 60 km, and azimuth coverage length of 134 km is presented. Furthermore, a simulation experiment on point targets was carried out. Both the presented system example and imaging results of point targets validated the proposed imaging mode.
传统斜视滑动聚束式合成孔径雷达（SAR）成像由于在整个数据采集间隔内斜视角度不断变化以及存在大范围单元徙动（RCM），存在条带宽度大幅减小和处理要求复杂的问题。提出了一种用于高分辨率宽测绘带（HRWS）成像的新型二维（2D）波束扫描模式。这种新型成像模式的关键在于方位向和距离向波束的同步扫描，从而能够实现具有高几何分辨率的更宽且更灵活的成像测绘带。采用从前往后的方位向波束扫描来提高方位向分辨率，同时采用距离向波束扫描来照射倾斜的宽测绘带，以避免大的RCM和严重的条带宽度减小。与传统滑动聚束模式相比，条带宽度和条带长度都可以得到扩展。根据这种成像模式的回波模型，提出了一种回波信号预处理方法。该方法的关键点是距离数据扩展和方位数据上采样。给出了一个设计的系统实例，其分辨率为0.5米，条带宽度为60千米，方位覆盖长度为134千米。此外，对点目标进行了仿真实验。所给出的系统实例和点目标成像结果都验证了所提出的成像模式。
