一种改进的Chirp Scaling成像算法

An Improved Chirp Scaling Algorithm

常规CS算法在算法推导过程中存在两个近似，即二维频率域泰勒展开忽略了距离频率的高次项以及二次距离压缩没有考虑调频斜率随距离的变化。随着SAR分辨率的进一步提高，由这些近似而引入的误差已不能忽略，不进行补偿成像效果将明显下降。该文提出了一种改进的CS算法，通过补偿距离频率的三次项，明显减小了算法的相位误差，使成像效果有明显改善，仿真结果验证了该方法的有效性。

There are two approximations in basic chirp scaling processing.First, there is the Taylor-approximation by neglecting higher order terms on range frequency. The second approximation is lack of updating the secondary rang compression with range. With the resolution higher, the efforts arising from approximations can＇t be neglected, which leads to degradations of image evidently. The paper presents an improved CS algorithm which evidently improves the phase accuracy by compensating the cubic polynomial on range frequency, improving the effect of the image. Simulations show that method presented in this paper is effective.