Direction-of-arrival estimation of wideband chirp signals in the presence of multipath propagation

In order to solve the problem of the performance degradation of existing wideband signal direction of arrival (DOA) estimation method in the presence of multipath propagation, a new DOA estimation method for multipath wideband chirp signals is proposed in this paper. This method is based on the steered effective projection (STEP) technique incorporating the time-frequency structure of wideband chirp signals. A spatial time-frequency distributions matrix rather than the traditional covariance matrix is used to construct the steered effective noise subspace with signal selectivity, based on which the multipath chirp signals can be distinguished and be tackled one by one. It is a time-domain scheme and requires no preliminary DOA estimates for data focusing, thus it is theoretically unaffected by focusing error. Moreover, both the time and frequency information of wideband chirp signals are used through the time-frequency distributions, which improves the estimation accuracy. The performance of the proposed method has been evaluated by extensive simulations, and compared with some current wideband DOA estimation methods.