The Research Of DOA Estimation In Coherent Signal Based On MUSIC Algorithm

Direction of arrival of space signals is regarded as a major topic in the field of array signal processing research, which has got more attention and study in recent years. The angle and location of source signals can be estimated precisely for the estimation of DOA in the space. High resolution of angle can be achieved when the method of DOA is used. Due to these features, the estimation of DOA has broad application and development in a variety of areas, such as sonar, radar, communications field and so on.As the space environment is complex in practical engineering, a number of coherent signals are contained in the data of signal received by radar. The frequency of the noise may bring about the phenomena of coherent. Sometimes the method of signal processing can lead to produce coherent signals. In the spatial spectrum estimation, the presence of coherent source signals leads to the problems of inaccurate targeting and losing locating ability. Many subspace algorithms which contain MUSIC and other methods are losing their abilities in facing of coherent signals. Therefore, how to process coherent signals has become a focus of study, which is the main contents of this article. Based on the traditional DOA estimation algorithm and the method of coherent signals processing which has been proposed, this paper has proposed its own algorithms. Here are the details of the main research work and contributions of this paper:1. Based on the model of signal and coherent signals which is used in ideal environment, this paper has introduced three algorithms which contain delay-addition method and Capon minimum variance method and MUSIC algorithm. Besides, this paper has described four algorithms about processing coherent signals including spatial smoothing method, singular value vector method (SVD algorithm), matrix decomposition method and Toeplitz algorithm. For the algorithms that have been mentioned, they have been analyzed in detail. And their advantages and disadvantages have been pointed in this paper.2. Combining earlier work, this paper has presented its own algorithm which is called I-MMUSIC, it is a combination of smoothing algorithm and MMUSIC algorithm. From the view of principle, the array preprocessing part and data processing part have been analyzed in this paper. Meanwhile, the calculation processing of I-MMUSIC algorithm has been given in this paper.3. This paper has designed program to verify the algorithm. Compared with spatial smoothing algorithm and MMUSIC algorithm, the precise I-MMUSIC is verified. Facing different value of SNR, the performance and stability of this algorithm have been proved through repeated simulation.4. The I-MMUSIC algorithm which is proposed in this paper has been applied to automotive collision avoidance radar. This paper has presented the complete process applitions about how to process signals in this kind of radar. The feasibility of this algorithm is proved by simulation, which provides a theoretical basis for the algorithm in practical engineering application.