一种改进的前斜视SAR距离多普勒成像算法

An Advanced Range Doppler Algorithm for Forward Squint SAR

摘要:

根据大斜视角SAR成像的空间几何模型和回波信号特点,提出了一种改进的适用于前斜视场景的距离-多普勒成像算法；对补偿二维频域耦合相位项的条件进行了分析,分析表明只需根据设计参数决定是否补偿到三阶耦合相位即可,且不必补偿更高阶的耦合相位；对距离徙动的校正方法进行了研究,通过在频域直接对距离徙动进行校正可以避免使用传统的插值方法,有效减小了计算量,提高了算法的运算效率,有助于算法的实时性实现；对改进的距离-多普勒算法的仿真表明,其成像性能能够满足前斜视条件下SAR实时成像处理的要求。

Abstract:

Based on the spatial geometry model of large squint mode SAR and echo response, an advanced range- doppler algorithm for forward squint-looking mode is presented in this paper. The condition of compensating coupling phase term in two-dimensional frequency domain is studied. Results show that only the third order coupling phase term required to be compensated according to the design parameter. Not having necessary compensating the forth or higher order coupling phase term. The method of range cell migration correction is studied. A modified method is proposed for correcting range migration in frequency domain to avoid interpolation. The modified method obviously decreases the calculated quantity and improves efficiency of the algorithm which contributes to the real time implement. The simulation results demonstrate that the advanced RD algorithm meet the requirement of SAR imaging in forward squint mode.