双天线前视弹载SAR解模糊算法研究

Study on Deambiguity Algorithm for Double Antenna Forward Looking Missile Borne SAR

前视弹载SAR中,航向两侧对称的目标具有相同的多普勒历程,从而造成了SAR图像的左右模糊。针对这一问题,该文基于弹载SAR的特点,建立了双天线前视SAR成像信号模型,详细分析了该体制下的信号特点。在此基础上,提出了一种解左右模糊的算法。该算法首先对双天线接收的雷达回波信号分别进行斜视成像,得到左右模糊的SAR图像,然后通过波束形成的方法、利用波程差解左右模糊,得到无模糊的目标图像。最后,通过成像仿真模拟,验证了算法的有效性。

Forward looking missile borne SAR suffers the issue of left/right ambiguity in SAR images because the targets situated symmetrically about the moving trace of radar have the same Doppler histories. Considering this issue, the imaging model of double antenna forward looking SAR is established based on the characteristics of the missile borne SAR, and the signal features in the double antenna system are analyzed. Based on the above analysis, a scheme is put forward to solve the left/right ambiguity. Firstly, two ambiguous SAR images are obtained with squint SAR imaging algorithm. Then the left/right ambiguity is solved by beam-forming based on range delay difference between different antennas. Finally, the point target imaging simulation testifies the validity of the proposed algorithm.