Studies On Technologies Of Wideband And Two-dimensional Array Direction-of-Arrival Estimation

A number of the superresolution direction-finding (DF) techniques have been proposed during 40 years and the basic theoretical framework has been formed. However, there are still many issues to be solved. Most of classic algorithms only pay attention to estimate DF under general situations. At present, with the development of the signal and antenna techniques, the signal and the antenna structure are showing a very strong application and structural characteristics, Such as wideband, signal-to-noise ratio (SNR), some special antenna structure and so on. The application of the characteristics of the antenna geometry structure and the signal sources will have a great effect to the superresolution DF techniques. Therefore, how to take full advantage of some signal sources and antenna geometry features is a hot topic in current research for DF techniques. Additionally, Sources number estimation is one of the important steps for exploiting DF techniques. The success of DF strongly depends on the correct estimation of sources number. So estimating the number of signals is also a hot topic of high resolution array direction finding technology.Along the hot topics mentioned above, this dissertation carries in-depth research to obtain a lot of results. The main work of this dissertation include studying the estimation of the sources number at low SNR, the sources number and DOA estimation for wideband signals, pair-matching, fast algorithm, array extension in two-dimensional (2-D) DOA estimation, how to make use of the structure of the array sensors together with the data properties for improving the performance of algorithm. The estimation performance of these methods is demonstrated, and the theoretical analysis is confirmed through numerical examples. The main innovation and creation are concluded as follows:Studying the array-based high resolution sources number estimation techniques. Using multi-channel data joint estimation idea to modify a sources number estimation technique based on blind beamforming methods. The simulation shows that the improved algorithm has better performance than the original algorithm, especially in low SNR and incident of unequal power signals.Studying the sources number estimation and DOA techniques for wideband signals. A novel algorithm with array extension properties is proposed. The proposed constructs pseudo-correlation matrix from this property, which is the each sub-narrowband in wideband signal corresponding to the different wavelengths. The sources number estimation part of the algorithm is of universal significance. Because from the mathematical point of view, the mainly idea of this method is to improve the Gerschgorin disk method, adapting the Gerschgorin disk method to toeplitz matrix without the hermite property. Owen to the current widely exploitation of the technology on constructing pseudo-correlation matrix based on making use of the features of the array structure and data, some of which are toeplitz matrix without the hermite property, this method could or make a little modification adapt this situation. So it makes up for some shortcomings in this area. The DOA estimation part of the algorithm has a strong array extension capability, the wider signal bandwidth, the stronger the ability of the array extension. At last, the algorithm was verified by a semi-physical simulation.Making an in-depth study on joint estimation of 2-D DOA for L-shape arrays, main researching how to utilize the structure of the array sensors and the data to improve performance. A fast algorithm based on the structure of the array sensors is proposed, which primarily through the use of pseudo-correlation matrix of the reduced-dimensional structure to achieve the purpose of quickly computing. the algorithm also has the automatic matching features. Also in L antenna array, a novel algorithm is proposed, which utilizes the physical structure and the relationship between signals to achieve automatic matching and array extension. This algorithm use Kronecker product and make use of some mathematical derivation of the matrix to conscious rearrange data. At last, an algorithm, which utilizes the array structure and the signal correlation time longer than the noise, is proposed. This algorithm can deal with colored noise and has the capability of array extension. Since the introduction of information on the physical structure of the antenna, the algorithm also has the ability to automatically match. In addition the accuracy of the three algorithms mentioned above performs well in similar algorithms.