基于自适应遗传算法的星载SAR天线方向图与模糊综合

Antenna Pattern and Ambiguity Synthesis of Spaceborne SAR Based on an Adaptive Genetic Algorithm

该文针对改善星载合成孔径雷达(SAR)的模糊特性,提出了一种自适应遗传算法。该算法同时对模糊和方向图进行优化。首先确定模糊区域,然后以天线方向图的主瓣宽度和副瓣电平(包括星载SAR模糊区域的副瓣电平)为目标函数,应用自适应遗传算法对天线方向图进行综合。为了避免早熟的现象,在该算法中,交叉概率、变异概率和变异范围同时进行了自适应的变化。和非自适应遗传算法相比较,该算法迭代步骤少,收敛速度快。仿真结果表明,模糊度得到了很好的抑制,对星载SAR系统设计具有实际意义。

In order to improve the Ambiguity-to-Signal Ratio （ASR） of spaceborne SAR, an adaptive Genetic Algorithm （GA） is proposed in this paper. By using the algorithm, ASR and antenna pattern are optimized simultaneously. Firstly, the ambiguity areas are determined, then the beamwidth and the side lobe level （including the side lobe level in the ambiguity areas of spaceborne SAR） of the antenna pattern are regarded as the objective function to synthesis the antenna pattern by using the adaptive GA. In order to avoid premature convergence, the crossover rate, the mutation rate and the mutation range are simultaneously adaptive during the optimization process. Compared to non-adaptive GA, the adaptive GA requires less iteration to converge and converges faster. The simulation results show that the ambiguity is depressed well via this method, which is quite useful to spaceborne SAR system designing.