通过对双基地逆合成孔径雷达(Bistatic-ISAR)回波信号模型进行分析,得出双基地ISAR回波信号在空间波数域的分布特性及其支撑区范围;在此基础上,提出了适于双基地ISAR的极坐标格式算法(PFA),该算法采用距离向线性插值和方位向非线性插值的方法实现极坐标到直角坐标的变换;此外,针对插值运算复杂度高的问题,在距离向插值中,引入Chirp-Z变换代替距离向线性插值,并结合方位向非线性插值提出了基于Chirp-Z变换的双基地ISAR的PFA算法;最后通过对点目标模型的仿真验证了所提算法的有效性。
A method called Polar Format Algorithm(PFA) suitable for the Bistatic-ISAR system is analyzed,the coordinate transformation from polar coordinate to rectangular coordinate is achieved by linear interpolation in range dimension and non-linear interpolation in azimuth dimension.Considering the complexity in interpolation,an improved PFA is proposed by using Chirp-Z transformation to replace the range dimension interpolation,thus reducing computational complexity greatly and obtaining the same effect as interpolation.Simulations of scatter points have demonstrated the validity of the proposed improved algorithm.