STAP with adaptive calibration of array mutual coupling and gain/phase errors

To address the significant degradation of Space-Time Adaptive Processing (STAP) performance when the array elements have mutual coupling and gain/phase errors, a STAP algorithm with adaptive calibration for the above two array errors is proposed in this article. First, based on a defined error matrix that simultaneously considers both array mutual coupling and gain/phase errors, a STAP signal model including these errors is given. Then, utilizing the defined signal model, it is demonstrated that the estimation of the defined error matrix can be formulized as a standard convex optimization problem with the low-rank structure of the clutter covariance matrix and the subspace projection theory. Once the defined error matrix is estimated by solving the convex optimization problem, it is illustrated that a STAP method with adaptive calibration of the mutual coupling and gain/phase errors is coined. Analyses also show that the proposed adaptive calibration algorithm only needs one training sample to construct the adaptive weight vector. Therefore, it can achieve a good detection performance even with severe non-homogeneous clutter environments. Finally, the simulation experiments verify the effectiveness of the proposed algorithm and the correctness of the analytical results.