一种SAR回波历程快速实时计算方法

A Fast Real-Time Calculation Method for SAR Echo History

针对合成孔径雷达(Synthetic Aperture Radar,SAR)目标回波模拟计算量过大的问题,采用两次多阶泰勒级数展开对回波系统函数中的距离历程进行计算,并结合数据外推的方法完成距离历程的快速实时计算。该方法使用多次乘法和加法代替计算量较大的开方运算,可保证在一定计算精度的前提下提高距离计算的实时性,同时结合距离历程模型的规律性,采用数据外推代替重复的计算过程,进一步降低计算量,提高实时性。通过仿真对比不同阶数泰勒级数展开在同一距离处的计算误差,得到了4阶为该仿真条件下的最优泰勒展开阶数,最后分别对9个分布密集的点目标和真实场景目标进行回波模拟和成像。点目标仿真结果表明,该方法在不影响回波信号性能的前提下可以使生成回波信号的时间减少53%,速度提升2倍;真实场景仿真结果表明,该方法可以应用于大场景的回波模拟。

Aiming at the problem that the simulation calculation of synthetic aperture radar(SAR)target echo is too large,two multi-order Taylor series expansions are used to calculate the distance history in the echo system function,and the fast real-time calculation of the distance history is completed by combining the data extrapolation method.This method uses multiple multiplications and additions instead of square root operation with large amount of calculation,which can ensure the real-time performance of distance calculation under the premi-se of certain calculation accuracy.At the same time,combined with the regularity of distance history model,data extrapolation is used instead of repeated calculation process to further reduce the amount of calculation and improve real-time performance.By comparing the calculation error of different orders of Taylor series expansion at the same distance,the fourth order is the optimal Taylor expansion order under this simulation condition.Finally,the echo simulation and imaging of 9 densely distributed point targets and real scene targets are carried out respectively.The point target simulation results show that the method can reduce the time of generating echo signal by 53%and increase the speed by 2 times without affecting the performance of echo signal.The real scene simulation results show that the method can be applied to the echo simulation of large scenes.