梯度投影最小二乘多途信道实数域高分辨估计方法

High resolution multipath channel estimation method of gradient-type least square in real number field

为解决水下定位过程中的多途信道高分辨估计问题,文章给出了一种梯度投影最小二乘多途信道实数域高分辨估计方法,不同于频域最小二乘,方法利用时域迭代求解去除了矩阵求逆,降低了计算量,并且能够直接获得高分辨的实数域信道冲激响应。与MUSIC、Richardson-Lucy (RL)以及稀疏贝叶斯(SBL)等几种典型时域高分辨信道估计算法进行对比分析,仿真和实验结果皆表明,文中给出的梯度投影LS算法和SBL算法时延分辨力明显优于MUSIC和RL算法,水池实验结果时延分辨力可达1/(5B)(B为信号带宽)。所提方法幅度衰减估计精度略差于SBL算法。但最小二乘(LS)算法使用过程中不需要预知多途数目,更适用于大时延多途扩展情况,且计算量显著优于SBL算法。

In order to solve the multi-path channel high-resolution estimation problem in underwater localization,a multi-path channel high-resolution estimation method in real number field based on gradient-type least squares is presented.The method reduces the computational effort by removing the matrix inversion from the time-domain iterative solution and directly obtains the high-resolution real domain channel impulse response,which is different from the method in frequency field.A comparative analysis among several typical time-domain high-resolution channel estimation algorithms,such as MUSIC,Richardson-Lucy(RL) and sparse Bayesian learning(SBL) is performed.The simulation and experimental results show that the gradient-type LS and SBL algorithms have significantly better time-delay resolution than the MUSIC and RL algorithms.The pool experimental results show that the time-delay resolution can reach 1/(5B)(B is the signal bandwidth) by using the proposed method.The amplitude attenuation estimation accuracy of the proposed method is slightly worse than that of SBL algorithm.However,the proposed method does not require the number of multipaths in advance,which makes it more suitable for large time-delay multipath extensions,and has significantly less amount of calculation than the SBL algorithm.