Direction Of Arrival Estimation On Coherent Signals Based On The Spatial Smoothing

Array signal processing is an important branch in the field of signal processing and the rapid development and application of radar, communications, sonar, seismic exploration and radio astronomy, as well as biomedical engineering, and many other areas of the national economy and the military sphere in the last 30 years .Signal processing array signal sensors are installed in a number of different locations of the space sensor arrays, and use this array signal field of space for receiving and processing to extract the signal received by the array and feature information, Inhibition of interference and noise, or not interested in the information. Array signal processing and general signal processing different, because its array layout mode for a certain amount of space in different locations on the sensor group, the main use of the airspace signal to enhance signal and effective information of the signal in the air. With the traditional single directional sensor, the array signal processing with flexible beam control, high-signal gain, strong anti-jamming capability and ultra-high spatial resolution capability advantages, which were of great concern, and this research work has been related to the development and depth, its scope of application have also expanded. At the same time as microelectronic technology, and digital signal processing technology, parallel processing of the rapid development of technology, the array signal theory and practical application has also been developing rapidly.In the actual environment, a source of radio signals, often through a number of channels at receiver antenna array, due to reflection of the way (such as buildings, valleys, vehicles, etc.), which could cause multipath propagation, a coherent source, Under such circumstances the classic method MUSIC,ESPRIT and the covariance matrix of rank is 1, wave direction to lead to inaccurate or even judge made an error of judgement on the accuracy of the positioning DOA have greater impact, therefore, the Coherent DOA estimates signal is the core of this paper.Classic MUSIC,ESPRIT, are one-dimensional signal DOA estimation methods, which are estimated on the basis of DOA, and the estimated two-dimensional signal DOA estimation study compared one-dimensional signal DOA more to the actual value, for example, in the communications, radar applications. This paper is one-dimensional coherent signal DOA estimation study by the improved TLS-ESPRIT method, and then the one-dimensional coherent signal DOA estimated on the basis of the two-dimensional coherent signal DOA estimates were studied, focusing on uniform Two parallel lines and the structure of L-type array.In this paper, firstly introduces the array signal processing in a number of important knowledge, and the uniform linear array model is described in detail. Secondly introduces signal source model and the statistical model of second nature on narrowband and broadband. In the third chapter focuses on the one-dimensional signal DOA estimation, the first focused on ESPRIT MUSIC and method of their performance and their respective advantages and disadvantages, followed because in real life applications, the signal reception reflected reason, a lot of formation Coherent signal, the failure of the method, detailed account of the spatial smoothing method, the method of small, easy-to-use. Based on the TLS-ESPRIT method in the case of small samples of the estimated performance is superior, and this will be the integration of spatial smoothing methods can be satisfactorily resolved coherent direction angle of the signal is estimated that this method avoid MUSIC based on the method of spatial smoothing peaks search, reduce the amount of computation.Taking into account the two-dimensional signal DOA estimates than the one-dimensional signal DOA estimated value of more practical applications, the paper on the one-dimensional basis of the estimated its outreach to the estimated two-dimensional study. Based on the pair of parallel linear array DOA matrix method is a more classic 2-D estimation methods, it does not need to search peaks, and signals natural match, DOA matrix smoothing method can be estimated coherent signal source, but they can not solve all " angle merger". This paper presents a parallel array based on double, through three small covariance structure of the matrix method, this method can be satisfactorily resolved "perspective merger", then this will be the method and space smoothing method combined, making it a coherent signals can be a good estimate, although in low signal to noise ratio of less than 2-D ESPRIT under way, but in high signal to noise ratio is very close to estimated performance, but should be less the amount calculated than after .L-type array consisting of two vertical line array, is a simplified plane arrays, it is simple in structure, a relatively small redundancy features, Chen Jian made based on the L-type array of 2-D DOA estimates method, this method using three covariance matrix structure a large matrix, as ESPRIT than two-dimensional methods of six covariance matrix structure an approach to reduce the amount of calculation and it is estimated effect ESPRIT is better than the two-dimensional method, but this method can not solve the coherent signals situation. In this paper, based on the L-type array of two-dimensional spatial smoothing method, the method can be coherent signal source under the direction of arrival angle correct estimate, it is estimated that the effective two-dimensional spatial smoothing ESPRIT law, and less calculated.