Narrow-band null phase-shift spatial filter based On oblique projection

Normal methods of spatial filtering methods may change the coherent characteristic of the target, which reduces the effect of accumulation in coherent systems despite the improvement of signal-to-interference and noise ratio (SINR). To avoid the amplitude and phase distortion introduced by the filters, null phase-shift spatial filter (NPSF) is proposed in this paper. NPSF can suppress the interference while keeping the original information of the target signal. However, the performance of NPSF will be influenced by the estimation error of the target´s spatial parameter. To solve this problem, an improved NPSF, narrow-band null phase-shift spatial filter (NNPSF), is proposed. The method to construct the weight vector of NNPSF is introduced. Theoretical analysis and simulation results demonstrate that the NNPSF is a valid spatial filtering technology. With reducing the accuracy of estimation, NNPSF is more suitable and robust in practical systems.