利用时差的单站无源相干定位最大似然算法

摘要

To solve the single-observer passive location estimation using multiple illuminators of opportunity,a time difference of arrival(TDOA) location algorithm based on maximum likelihood is proposed.Firstly,according to the functional relationship between the TDOA measurements and the target location,the likelihood function of the target location is constructed.Then Newton's method is applied to obtain the global maximum of the nonlinear likelihood function and determine the target position.The least squares solution of the target location is derived and used as the initial guess of the Newton's method.Finally,the theoretical error and the Cramer Rao Lower Bound (CRLB) are also derived and proved to be equal.Simulation results demonstrate that the proposed algorithm outperforms existing algorithms and achieves the CRLB at moderate noise level.Moreover,from the geometric dilution of precision figure,the influence of target position,illuminator number and position on the localization accuracy is analyzed.%针对利用单个观测站接收多个第三方辐射源信号来估计目标位置的无源相干定位问题,提出了一种基于最大似然的时差定位算法.首先根据时差测量与目标位置之间的函数关系,构建目标位置的似然函数;然后采用牛顿迭代算法求解非线性似然函数的全局极大值,从而得到目标位置估计;推导了目标位置的最小二乘解,并将其作为牛顿迭代的初始解,从而保证算法的收敛性;最后还推导了算法的理论误差和克拉美罗界,并证明两者相等.仿真结果表明,算法的定位精度优于现有算法,且在测量误差适中时,定位精度可以达到克拉美罗界.通过几何精度因子图,分析了目标位置、外辐射源数量和位置等因素对定位精度的影响.