一种基于相位补偿的前向散射阴影逆合成孔径雷达快速成像方法

摘要

传统的基于菲涅尔数值积分的前向散射阴影逆合成孔径雷达(SISAR)成像计算复杂且运算量较大。为提高运算速度，该文对SISAR快速成像方法进行了研究。首先提出一种基于快速傅里叶变换(FFT)的SISAR快速成像方法，并给出了FFT引入相位误差的补偿公式；随后通过对运动补偿后信号频谱进行分析给出了SISAR成像的采样准则，其指出成像所需的信号采样率可以远小于奈奎斯特采样率。仿真结果表明，利用FFT和低采样率的快速成像方法可以在精确成像的基础上大大降低运算量，具有实际工程意义。%The numerical calculation of forward scatter Shadow Inverse Synthetic Aperture Radar (SISAR) imaging is usually performed by the Fresnel numerical integral which is complicated and time consuming. To improve the calculation speed, the fast SISAR imaging method is investigated. Firstly, a fast imaging method based on the Fast Fourier Transform (FFT) is proposed while the phase errors introduced by the FFT are compensated. Then, through the analysis of the spectrum on the motion compensated signal, the sampling law for SISAR imaging is given, indicating that signals used for imaging can be sampled at a rate much lower than the Nyquist sampling rate. Simulation results show that the proposed fast imaging method can give accurate profiles and significantly reduce the computation, which is of practical meaning in engineering application.