Angular superresolution for phased antenna array by phase weighting

In this paper, a new angular superresolution technique called Phase Weighting Superresolution Method (PWSM) is proposed. The method combines a phase weighting method and a nonlinear spectral estimation algorithm. It is used in conventional phased array radar for improving angle resolution. The motion compensation of radar target and an analysis of influence of component imperfection in the realization of the method are presented. To evaluate the performance of the proposed method, Monte Carlo simulation has been conducted to estimate the root mean square error (RMSE) of the angle estimates and the spatial resolution signal-to-noise ratio (SNR) threshold in the cases of both non-fluctuating targets and fluctuating targets. The simulation results have been compared to those of beam space MUSIC method and the Cramer-Rao lower bound (CRLB). Numerical and experimental results show that good angular superresolution and high estimation accuracy can be achieved provided that the radar pulse repetition time is small enough so that the echoes can be considered sufficiently correlated. For an X band conventional phased array radar with 139 antenna elements, by using PWSM the angular resolution is improved by a factor of 2 when SNR equals 15 dB.