Distributed Subarray Antennas(DSA) have been presented to satisfy the need for high -resolution and high-gain radars, especially for shipborne radar platform due to limited surface available. Coherent combining the distributed apertures leads to the grating lobes in beampattern or ambiguities in direction of arrival (DOA) estimation. By exploiting the low-rank matrix completion theory and positive definite programming, an ambiguity resolution algorithm is proposed. It accomplishes high resolutio