Sparse mutual coupling matrix and sensor gain/phase estimation for array auto-calibration

This paper develops a method for estimating the sparse array mutual coupling matrix and sensor gains/phases using a signal source at unknown directions. The sparsity of the mutual coupling matrix results from the recognition that the mutual coupling between array elements is inversely related to their separation and may be negligible for elements separated by a few wavelengths. We remove the restriction that the signal test source directions must be known, as required in an earlier recent work by the author (see Jaffer, A.G., Proc. 35th Asilomar Conference on Signals, Systems and Computers, 2001). A fast converging iterative method is developed which estimates the directions and the sparse mutual coupling matrix and sensor gains/phases. Computer simulation results are presented to demonstrate the utility of the method.