Selection Of The Optimal Focusing Frequency And The Influence On The Performance Of Coherent Signal-Subspace Method By Focusing Frequency

As an important part of the modern signal processing, direction of arrival (DOA) estimation has wide applications in many fields. The current estimation methods pay more attention to narrow-band signal. With the development of communication technology, wide-band signals are used more and more widely in communication systems. On the other hand, there are many wide-band signals in nature, such as seismology wave, acoustic signal. So the research on wide-band DOA is becoming more and more important.Wide-band DOA estimation methods are developed from narrow-band methods. Now there are two classic wide-band DOA estimation methods: maximum likelihood method (MLM) and signal subspace method (SSM). SSM includes that incoherent signal-subspace method (ISM) and coherent signal-subspace method (CSM). The dissertation has studied CSM and the main achievements are summarized as follows:1. The fundamental concepts and theories of DOA in array signal processing have been discussed, and the model of wide-band array signal processing has been set up. 2. Wide-band DOA estimation methods are developed from narrow-band methods, so the dissertation has studied two methods: Capon method and MUSIC method, and compared the performance of two methods through simulation.3. The dissertation has introduced ISM simply, and studied especially that theory of CSM and rules of forming focusing matrixes. The select principle of the optimal focusing frequency has been particularly introduced and more explained through simulation. The innovations include that the effect on focusing error and CSM by different frequency has been analyzed, the optimal frequency and the character of non-unique at the optimal frequency has been found.