基于卡尔丹方程的高分辨ROSAR成像算法及性能分析

High resolution imaging algorithm and performance analysis for ROSAR based on cardano's formula

旋转式合成孔径雷达(rotor synthetic aperture radar,ROSAR)是一种新型的雷达成像模式,其圆形运动轨迹斜距历程造成传统二阶斜距近似法在宽方位波束场景下方位向散焦严重。针对这一问题,提出了一种基于卡尔丹方程解析表达式的ROSAR成像算法。考虑通过对回波信号的斜距表达式进行四阶近似,推导了回波信号的二维频谱,分析距离徙动对成像结果的影响,提出基于卡尔丹方程解析表达式实现距离徙动补偿,进而实现整个场景精确聚焦的成像算法并给出了算法的运算量。仿真实验验证了算法的有效性及在噪声环境下的稳健性。

Rotor synthetic aperture radar （ROSAR） is a new kind of imaging mode, due to the complex expression of target＇s range derived by its circular trajectory of motion, expanding target＇s range to the second or- der brings severe defocussing in azimuth under the condition of wide-beam. To deal with this problem, a new imaging algorithm of ROSAR based on Cardano＇s formula is proposed. Considering expanding the expression of targeUs range to a fourth order polynomial and deriving the two-dimensional spectrum of echo, an effect of range cell migration （RCM） on image is made. The image is obtained by compensating RCM based on Cardano＇s formula and the calculated amount of method is showed. Simulation results validate the feasibility and the robust in noisy environment of the proposed algorithm.