基于Chirp Scaling的双基SAR成像PFA算法研究

摘要

This paper investigates an implementation of Polar Format Algorithm(PFA) in Bistatic SAR imaging based on the principle of Chirp Scaling(CS). PFA realizes data's Polar Coordinate Transformation by two 1-D interpolations, which is computationally expensive. Based on the linear frequency modulation characteristic of emission signal, the paper uses Chirp Scaling methodology to process data in range dimension, which only includes signal multiplications and FFTs, thereby avoiding interpolation. The chirped and dechirped signals are discussed separately. Compared with interpolation, the results are equivalent, but the method of CS has increased speed significantly. The experimental simulation results with the point target validate the validity of this method.%该文研究了基于Chirp Scaling原理实现双基聚束SAR成像的极坐标格式算法(Polar Format Algorithm, PFA).PFA通过两个一维插值来实现数据的极坐标格式转换,插值计算量较大.该文基于发射信号的线性调频特性,在距离向对极坐标格式数据进行变标处理,仅包含信号复乘和FFT,从而避免了插值运算.文中对于接收Chirp信号和Dechirp信号分别进行了讨论,依照不同流程实现了极坐标格式算法.同插值方法相比,二者聚焦结果相当,但是CS(Chirp Scaling)的方法速度有显著提高.点目标仿真实验验证了此方法的有效性.