Antenna array calibration is an important task. In this paper, an online calibration method is proposed for antenna arrays where the antennas have unknown gain/phase mismatch and mutual coupling. The mutual coupling matrix is unstructured and the array is randomly deployed on a plane. Two reference sensors are assumed to be perfectly calibrated. The proposed technique uses higher order statistics (HOS) and the reference sensors to estimate the direction-of-arrivals (DOA) of multiple signals. The gain/phase mismatch and mutual coupling parameters are also estimated with a direct approach. Several simulations are done to show the effectiveness of the proposed method.