SAR大斜视RMA快速成像算法研究

Study on Fast RMA Imaging Algorithm of High Squint SAR

在快速成像问题的研究中,针对常规距离徙动算法RMA中STOLT插值引起的高计算开销、效率低,不能有效进行快速成像的问题,提出了一种将非均匀傅立叶变换NUFFT和RMA相结合大斜视快速成像算法。通过详细分析大斜视SAR回波信号的时频特性,介绍了NUFFT算法原理以及实现步骤。再采用NUFFT代替STOLT插值和距离向IFFT,实现频域非均匀的格点向时域均匀格点变换。仿真结果表明改进后算法具有较高精度,同时兼顾了效率,满足大斜视SAR成像要求,并且为SAR成像算法中非均匀时频变换提供了一条新途径。

To decrease the computation burden of STOLT interpolation with enhanced efficiency and fast imaging in Range Migration Algorithm （RMA） for high squint Synthetic Aperture Radar （ SAR）, an improved fast imaging al- gorithm based on non-uniform fast fourier transform （NUFFT） was proposed. First, the time-frequency characteris- tic of high squint SAR echo signal was analyzed in detail. Then the principle of NUFFT and its implementation were introduced. Finally, NUFFT was used to substitute the STOLT interpolation and range IFFF to fulfill the transform be- tween non-uniform frequency domain data and uniform time domain data. Simulation results illustrate that the im- proved algorithm possesses high precision, improves the computation efficiency, satisfies the imaging quality of SAR in high squint mode and provides an innovative approach for non-uniform time-frequency transform in SAR imaging algorithm.