三阶多项式相位信号参数估计

Parameters estimation for cubic phase signal

三阶多项式相位信号常用于描述复杂运动目标的雷达回波,但其未知参数多,参数估计实现起来比较困难。针对此问题,本文提出了一种分两步的三阶多项式相位信号参数估计方法:首先利用Radon变换提取三阶多项式相位信号在三次相位变换后对应的直线,从而得到相位参数的初始值估计;然后将初始值代入最大似然估计函数并利用单纯形法对其进行优化得到精确估计结果。给出了单分量和多分量情况下的参数估计流程。仿真结果表明,本文算法估计性能达到CRB界,且起始工作信噪比门限低。

Cubic phase signal is always used to model the radar echoes from complex moving targets, but it contains a lot of unknown parameters and has much difficulty in its parameter estimation. Motivated by this, a method contains two sub-steps is present in this paper to estimate the parameters of cubic phase signals. Firstly, the Radon transform is used to extract the straight line which corresponding to a cubic phase component after doing cubic phase transform for signal, thereby, the initial value of the phase parameters can be obtained. Then, the simplex method is utilized to optimize the maximum likelihood estimation function to get the accuracy estimating results and the initial value can be used to initialize the optimization process. The procedures for single-component and multi-components cubic phase signal parameters estimation are presented. Simulation results showed that the algorithm can works at a low signal to noise ratio threshold and reaches the CRB.