Analysis of Effects of System Mismatches on the Performance of Adaptive Generalized Sidelobe Canceller and Compensation Methods

The effect of system mismatches on an adaptive linear constrained generalized sidelobe canceller (LC-GSC) is discussed in this paper. Based on the array gain index, two classic system mismatches, the direction of arrival (DOA) mismatch and the mismatches arising from array disturbance, are studied, respectively. To obtain the effective methods for compensating for the system mismatches, we analyze the performance of the improved LC-GSC with the diagonal loading and additional constraints (such as the directional constraints and derivative constraints). The computer simulations show that the techniques of diagonal loading and additional constraints can effectively compensate for the system mismatches. The loss of array gains can be controlled within 3 dB in the presence of 20% of array disturbances or DOA mismatch when the signal-to-noise ratio is less than 10 dB. The analysis illustrates that the proposed compensation methods are valid and feasible.