In this dissertation, the problem of target tracking in the presence of electronic counter measures (ECM) with phased array radars is studied. This work focuses mainly on tracking airborne targets in the presence of strong interference. This research also proposes novel data association techniques to improve the track performance in the presence of strong interference. This work further deals with tracking closely spaced targets in the presence of ECM. An investigation is carried out to resolve the closely spaced targets using Stockwell transform based multiple signal classification (MUSIC) direction of arrival algorithm. This method yields improved performance compared to that obtained from other existing methods.