Direction Of Arrival Estimation On Coherent Signals With Array Errors

Array signal processing is a new field of signal processing, and it is a very important content of modern signal processing. Array signal processing has wide engineering application such as radar, sonar, weather predicting, land and ocean exploring, seismic and biomedical signal processing etc. On different spatial positions, a few of sensors are placed by some rules so that these sensors form an array of sensors. Though the type of these sensors may be different, the function of these sensors is the same, that is, the interested spatial information is connected to signal processor. By the array of sensors, the electromagnetic wave is sent or the spatial signal is received. So the information of spatial sources is gained by signal processor. The process above is called as array signal processing. The aim of array signal processing is to get the useful information of spatial sources with the received signal.Spatial spectrum estimation is an important area in array signal processing ,which is developing rapidly in recent thirty years and emphasizes particularly on the capability of the spatial multi-sensor array system's the accurate estimation for the parameters of the interested spatial signals. To estimate the spatial parameters and the location of the signal sources is the spatial spectrum estimation's purpose, which is used in some fields, such as radar, communication and sonar etc. Spatial spectrum is an important concept in array signal processing, which denotes signal's energy distribution in all spatial directions. If we get signal's spatial spectrum, we can get signal direction of arrival, so spatial spectrum estimation is usually named"DOA"estimation. The basal question of DOA estimation is to make certain the location of multiple concerned signals co-existing in some spatial fields. In another word, to decide the direction angles of the signals on arriving at the reference array units.At first, this paper introduces some elementary knowledge about array signal processing, then stresses on the math model and statistical model of the uniform linear array. Furthermore it provides several general DOA estimation methods such as MUSIC and ESPRIT, and demonstrates their performance with computer simulation. However, in reality, due to the impact of the multi-path aspects, there are many coherent signal sources in space. At this time, the performance of general DOA estimation methods will greatly deteriorate because the signal subspace and the noise subspace influence mutually. Therefore, the DOA estimation of the coherent signal sources is a hot research problem. For several decades, many scholars have done lots of research, and made a big progress. But, most methods are all based on the ideal array. However, in reality, some array errors is inevitable such as array location error, mutual coupling etc, which is bound to affect the performance of the original DOA estimation methods. So it is very necessary to correct array errors when estimating DOA of the spatial coherent signals, which is the creativity of this paper.As above, the fifth chapter of this paper discusses the realizing of the method which includes the spatial coherent signals DOA estimation for the uniform linear array location error and array unit mutual coupling error. These methods have less computational costs, high resolution and good robust. Through the computer simulation and comparing with former methods, the provided methods prove to be valid, correct and practical.