The performance of space–time adaptive processing (STAP) radar degrades dramatically when the target occurs in the training data. Traditional robust linearly constrained minimum variance (LCMV) STAP method uses magnitude constraint to maintain the mainlobe of the STAP beamformer. In this paper, a joint magnitude and phase constrained (MPC) STAP method is proposed with the phase constraint incorporated in the response vector of the beamformer. The explicit expression of the phase constraint is derived by exploring the conjugate symmetric characteristic of the adaptive weights. With joint magnitude and phase constraints imposed on several discrete points in the mainlobe region, the MPC-STAP approach has good robustness against target contamination. In addition, the linear-phase response can be guaranteed by the proposed method, which provides distortionless response in both spatial and temporal domains. Simulation results are provided to demonstrate the effectiveness of the proposed method. 
Joint magnitude and phase constrained STAP approach