一种新的SAR图像斜距多普勒定位模型的直接解法

A New Direct Solution of Range-doppler Model for SAR Image

斜距多普勒定位模型是实现SAR图像无控制点定位的基本模型,因此如何高效准确地获得RD方程组的解成为实现SAR图像无控制点几何定位的根本问题,也是实现SAR自动图像定位的关键。首先利用地固坐标系下目标速度为零的特性,简化RD模型并整理为一元四次方程,然后利用一元四次方程求根方法,推导出斜距多普勒定位模型的明确数学解析解,并与常用的数值迭代求解方法进行比较分析,仿真结果验证了推导的正确性。新解法具有无需设置初始值,易于编程实现,鲁棒性高的特点。

The Range-doppler model is a basic model for SAR image locating without GCP. So obtaining the solution of RD equations accurately and efficiently is an essential question for SAR image location without GCP. It is also the key step of SAR automated image location. In this paper,the RD model has been simpli- fied to quartic equation with one variable based on the characteristic that the object＇s velocity equals to zero in Earth Centered Rotating. The paper deduces an analytical solution of Range-doppler model by solving the quartie equation. This paper compares the analytical solution with numerical solution by simulation. The results show the analytical solution is feasible and validity. The new solution has three advantages：no setting initial value, easy to programming realization and high robustness.