Maximum Likelihood Angle Estimation of Target in the Presence of Chaff Centroid Jamming

Chaff centroid jamming released by vessel causes the indicated angle of radar seeker of anti-ship missile to deviate from the target. The failure to track the target is catastrophic for the radar seeker. In this paper, the angle estimation of the target in the presence of chaff centroid jamming is investigated. In the circumstance of chaff centroid jamming, the jamming is usually in the same range and angle resolution cells as the target. Under these circumstances, the essence of this problem is to estimate two unresolved targets' angles in the main beam of the radar seeker. To this end, two alternative methods are proposed to estimate the direction of arrival of the target in this paper. First, we present a maximum likelihood (ML) method implemented by a 2-D numerical search, which has high estimation accuracy but large computational load. Subsequently, considering both the accuracy and computational load, an improved ML (IML) method is developed. Based on the ML method, the proposed IML method adopts a search optimization processing by moment estimation. Furthermore, the effects of some key factors on the estimation performance are analyzed. The accuracy of the proposed methods is compared with the existing methods and the Cramer Rao lower bound as well.