Methods Of Array Signal Processing Of Phased Radar

It has more than twenty years since the eigen-decomposition spatial spectrum estimation algorithm was presented. And a lot of efficient methods have been proposed. But most of them are based on the element outputs of the array, namely method at element level.Phased array system is an important application field of spatial spectrum estimation techniques. In large phased array systems, the array may be consisted of thousands of elements, at this time, the subarray structure is usually employed and only the digital subarray outputs can be obtained. In this case, the present proposed direction finding algorithms based on element level are no more suitable; we can only but use methods at subarray level.2-D superresolution direction finding methods at subarray level suited for plane phased arrays are studied. For overcoming the limitations of true array manifold (TAM) that the expense and cost of the array calibration are high and the calibration realization is complex, five kinds of simplified array manifolds are proposed, namely direct simplified array manifold (DSAM), simplified array manifold based on ideal subarray patterns (SAM_ISP), simplified array manifold based on approximate ideal subarray patterns (SAM_AISP), simplified array manifold based on Gaussian subarray patterns (SAM_GSP), simplified array manifold based on approximate Gaussian subarray patterns (SAM_AGSP) respectively. The performances of applying these array manifolds to MUSIC, WSF and ML methods at subarray level are analyzed. The WSF method and ML method can be used in direction finding of coherent sources. We find that TAM has the widest direction finding range while the available direction finding ranges of the DSAM, SAM_ISP, SAM_AISP, SAM_GSP and SAM_AGSP are in a certain area centered at the look direction. The SAM_ISP, SAM_AISP, SAM_GSP and SAM_AGSP can change the effective direction finding ranges by adjusting their inner parameters and furthermore they can improve the sidelobe suppression effect compared with the DSAM method. Applying simplified array manifolds can reduce the array calibration cost, and compared with the TAM method, these simplified array manifolds can make the multidimensional...