Research On Wideband Signal DOA Estimation Algorithms

Spatial spectrum estimation is one of the main research directions of the array signal processing, it focuses on the estimation ability of multifold signal parameters. The main purpose of spatial spectrum estimation is estimating the airspace parameters or location of the signal, it has a broad application prospect in many fields such as radar, communication and sonar.So far, direction-of-arrival (DOA) estimation algorithm about narrow-band signals is comparatively mature. Wideband signal has the merit of more information, which is good for targets detecting and parameters estimation, thus research on wideband signal DOA estimation algorithms makes important practical significance. But wideband signal processing is in need of further enhancing its estimation performance with the greatly increased research in this area. Based on uniform linear array, this thesis makes a research on wideband signal DOA estimation algorithms and array errors calibration problem. The main work is summarized as follows:1. The classical narrow-band high-resolution DOA estimation algorithms have been discussed, the performance of MUSIC and ESPRIT algorithm have been analyzed through computer simulations. ISM algorithm that is applied in incoherent broadband signal has been researched, and the thesis presents an improved ISM algorithm to deal with coherent wideband signal.2. In allusion to the actual existence of a large number of coherent broadband signals, the thesis has an in-depth discussion on the principle of classical CSM algorithm. The key problem is the structure of focusing matrix, which generally requires an estimation of initial angle and the selected frequency to determine the focusing matrix. Primary values make a great impact on the effect of CSM algorithm. Through the simulation results, the performance of several algorithms have been comprehensively analyzed and compared. DED algorithm that does not require the position estimation has been discussed.3. Based on the CSM algorithm, the thesis presents a new algorithm to estimate coherent wideband signal. It applies the principle of spatial smoothing algorithm to wideband signal DOA estimation, in order to reduce the impact of the array errors. The simulation results show that this algorithm can improve the ability to solve coherent signal and it has high stability.4. CRB of wideband high-resolution DOA estimation have been discussed, it can determine the limit of resolving power by analyzing the CRB of algorithm. For array errors are inevitable, to overcome its bad influence, the thesis introduces narrow-band array error models and three kinds of error calibration methods, and a broadband array errors calibration method.