Channel balance is the prime problem for target parameters estimation and location.We focus on channel mismatch and target signal contamination which preclude the performance described in much of the theoretical space-time adaptive processing (STAP) literature.Exploring phase relation among along-track Doppler beam sharpening (DBS) images

a channel calibration algorithm based on second order moments of phase vector is presented.The effectiveness for channel mismatch and the robustness for target signal contamination are confirmed by performance analysis and experimental data.