DOA Estimation Of Wideband Signals Based On Signal Subspace Method

Array signal processing is an important means of analysing and processing spatial signals. In various application domains, such as radio,sonar,seismology and expand-frequency communication etc, multiply wideband signals DOA (Direction of Arrival) estimation becomes more and more important. This dissertation is devoted to the study of wideband signal DOA estimation, including Incoherent Signal Subspace Method (ISM) and Coherent Signal Subspace Method (CSM).The main work is listed as follows:1,The wideband singal model is constructed ;And the wideband signal DOA estimation based on signal subspace method is introduced detailedly; The typical methods of wideband signal processing is analysed, numerical simulations prove their efficiency.2,The ISM is simulated to show this method will be affected in case of coherent signal sources. A modified ISM , which combines with progator method and make use of cross-correlation matrix of received data, is proposed to overcome this problem. Numerical simulations show that the modified method owns a better resolving power and theoretic analyse is presented to explain the computation load of this new method is much smaller.3,The alpha stable distribution is introduced; Simulations show that CSM is deteriorated in the presence of alpha stable distribution noise, the flom (fractional lower order monment) is applied to the CSM, so this new method can work in alpha stable distribution noise environment. And a modified flom-CSM is proposed, which used wighted data matrix to get rid of the effect from the noise. Compared with the flom-CSM, the modified flom-CSM is more robust.