一种基于余弦特性的快速DOA估计算法

A fast DOA estimation method based on cosine characteristic

  • 摘要: 为了满足实时测向处理系统的要求,需要降低测向算法的运算量。在众多测向算法中,其中基于圆阵的MUSIC类算法因为其测向频段宽,可估计二维波达方向,性能稳健,测向精度高,并且在各个方向上具有相同的测向性能而广泛应用于实际系统中。本文主要针对均匀圆阵的阵列流形,分析了均匀圆阵导向矢量的特点,提出了一种基于余弦特性的快速DOA估计算法。该算法利用余弦信号周期特性来构造统计量,通过数学推倒可以证明该统计量只与俯仰角有关,与方位角无关。通过这种分维处理的思想从而可以先估计出俯仰角,再通过所得俯仰角的空间谱切片把二维搜索转化为一维搜索,这样处理大大降低了算法运算量,提高了算法估计速度,特别适合阵元数目较多的应用场合。同时考虑到实际应用中在同一个窄带信道中干扰信号和期望信号同时存在,并且互相影响,特别是强信号对弱信号的影响。本文利用数字滤波器提取期望信号估计,减少了干扰信号对期望信号的影响,提高了估计精度。通过计算机仿真验证了该算法的有效性。

     

    Abstract: The complicated operation of finding direction must be reduced to satisfy the real time finding direction processing. Now, there are many finding direction algorithms. The MUSIC like algorithm based on the uniform circle array is applied to the practice system. Because this algorithm has width frequency ranges. Both of the elevation and azimuth can be estimated. This algorithm also can provide accurate estimation efficiently. The performance of this algorithm is solidity and robust. The direction of arrival estimation has the same capability from the different azimuth. Analysis is done on the steering vector of the uniform circular array aiming at the geometry of the uniform circular array. Then, a fast DOA estimation method based on cosine characteristic is put forward. First, this method constructs the statistical variable. This variable has relation with elevation only, which has no relation with azimuth. So the estimation of elevation angle can be get by cosine characteristic. Then, the two dimensional search is replaced by the one dimensional search by the estimation of elevation angle. The complicated operation of finding direction is reduced consumedly. This algorithm can provide accurate estimation efficiently. This algorithm is suited to applied situation of the many array number. Compared with the existing 2-D direction of arrival estimation algorithm, the superiority of this algorithm is evident in the computational load. At the same time, there are two signals in the practice narrowband system. The two signals interacts each other. This paper distills the anticipant signal by digital filter to reduce the effect on small signal. The simulation results validate the efficiency of the method. Performance of this algorithm is robust than the other algorithms. Compared with the existing finding direction algorithm, the superiority of this algorithm is evident in the computational load.

     

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