Robust bi-iterative STAP algorithm against DOA and Doppler mismatches based on SOCP

To solve the problem of the direction of arrival (DOA) and Doppler mismatch errors between the actual and presumed signal steering vectors in airborne radar spacetime adaptive processing (STAP), a robust bi-iterative STAP algorithm based on second-order cone programming (SOCP) is proposed. Explicit models of uncertainties in both temporal and spatial signal steering vectors are considered. It is shown that the robust STAP problem can be solved by minimizing a convex quadratic cost function based on the optimization of worst-case performance when full degrees of freedom (DOFs) are used. The quadratic cost function is further reformulated into a bi-quadratic cost function by adopting a separable form for the weight vector and the optimum solution of the new cost function can be efficiently obtained by combining bi-iterative algorithm (BIA) with SOCP. The proposed method can achieve the robust STAP performance while significantly decreasing the training sample requirement and the computational complexity, which is more valuable for practical engineering application. Simulation results are provided to demonstrate the effectiveness of the proposed robust STAP method.