临近空间慢速平台SAR快速成像模式研究及算法研究

临近空间慢速平台合成孔径雷达成像效率低，本文提出一种方位向多波束切换成像模式，实现其对地面区域的快速成像。其基本思路为将方位向测绘带划分为多个子测绘带。同时将所需方位向采样率提高相应倍数。在方位向各采样点周期性的照射方位向各子测绘带。对比传统条带成像模式，本文提出模式可有效提高慢速平台成像效率。当方位向子波束个数足够大时，其方位向成像效率可快于快速平台。所提出的成像模式可同时实现对地面的高分辨率宽测绘带成像。本文给出了系统设计关键参数的计算公式及信号处理流程。仿真结果验证了本文提出成像模式及信号处理流程的有效性。 

Fast Imaging Mode and Algorithm of SAR in Near Space Slow Platform

The imaging efficiency of the synthetic aperture radar installed in near space slow platform is low. In this paper an imaging mode based on the azimuth multi-beam switching is proposed. The basic idea is to divide the azimuth swath into multiple azimuth sub-swaths. The required pulse repeated frequency is increased accordingly. In the azimuth sampling positions, the azimuth sub-swaths are illuminated periodically. In contrast to the traditional stripmap mode, the proposed mode can improve the imaging efficiency effectively. When the number of the multi-beam is large enough, the imaging efficiency of the slow platform can be higher than that of the fast platform. The high resolution wide swath imaging, meanwhile, can be achieved. The formulas for calculating the key parameters of the system as well as the signal processing steps are provided. The simulation results verify the validity of the proposed imaging mode and signal processing steps.