Research On A Hexagonal Array Mutual Coupling Error Calibration Method

In recent decades, spatial spectrum estimation technique is a new and rapidly developed emerging spatial signal processing technology, and its main objective is to study how to improve the estimation precision of signal space angle, the angle resolution and speed of algorithm. Spatial spectrum estimation technology main research direction of arrive(DOA) of spatial signal, and the merits of spatial spectrum estimation are quite obvious, including the high precision of DOA, the high resolution performance, and the ability to estimate direction of arrive of multiple signals at the same time. However, in practical engineering, because of the array mutual coupling error, some deviations would be caused between the real array manifold and theoretical one, which make the performance of spatial spectrum estimation algorithms reduced or even failure, so it is always a difficulty of the study of spatial spectrum estimation algorithms. Relative to other forms of error, mutual coupling error calibration is a more unknown parameters and the relatively complex error calibration method, the array mutual coupling error calibration has been difficult to find a simple and effective method for the calibration of the array mutual coupling, so the research of mutual coupling error calibration method is an important focus of the current problems.This paper focuses on these problems deeply analyzes and researches the calibration method of array mutual coupling error. This article introduces the foundation of the spatial spectrum estimation, and two type of typical and high-resolution DOA estimation algorithm. Based on DOA estimation, this paper introduces the common array error and focuses on the mutual coupling model, thus, this paper introduces mutual coupling error model of several kinds of common array. Mutual coupling error calibration method is divided into two categories: the mutual coupling calibration method based on the instrumental sensors and mutual coupling self-calibration method. The instrumental sensor method is mainly by introducing a number of instrumental sensors to realize the array mutual coupling error calibration, the algorithm does not require iterative arithmetic and there is no local optimal solution. Since the self-calibration method is mainly introduced the MUSIC iterative method and the rank defect mutual coupling calibration methods, the MUSIC iterative method makes the mutual coupling problem into a joint multi-parameter estimation problem in order to realize the error of estimation array coupling, and finally to complete calibration of the mutual coupling error by mutual coupling compensation. The rank defect method avoids the multidimensional search and the problem of local convergence in the iterative process. Then, this paper analyzes and studies the mathematical models and structural characteristics of the hexagonal array, using the uniform linear array structure and mutual coupling characteristics, it presents an applicable to hexagonal array mutual coupling error self-calibration algorithm, which has realized the combination of DOA and array mutual coupling coefficient estimation. It has a small amount of computation and the estimated high accuracy. Finally, the performance of the mutual coupling calibration method of DOA and mutual coupling error parameter estimation is verified by computer simulation experiments.