DOA estimating based on non-uniform signal recovering algorithm in multi-carrier frequency MIMO HFSWR

Multi-carrier frequency is adopted in MIMO HFSWR system so as to get better angle resolution and reduce the physical size of the Uniform Line Array (ULA), which has superiority compared with single carrier frequency. Better angle resolution than real array is achieved as the consequence of a Virtual Non-uniform Array (VNLA) with extended aperture, which is obtained by the utility of large spaced carrier frequency combination. However, the classic MUSIC can only be used to handle non-coherent sources with the VNLA. After using the proposed non-uniform signal recovering algorithm, the recovered uniform sampled data of the Virtual Uniform Linear Array (VULA) is used in the DOA estimating of sources. In order to take advantage of the increased degree of the VULA, we skip noise pre-whitening and employ more sub-arrays of the VULA for Forward-backward Spatial Smoothing (FBSS) which plays a key role in noise floor reduction as well as in coherent sources de-correlation.