Comparison of methods for tracking separating targets with a monopulse radar

In many tracking applications, and particularly those in ballistic missile defense, one concern involves the continuous tracking of an object that separates into two objects. Reliable tracking without track breaks demands early recognition of such a split, preferably well in advance of the two objects becoming resolvable by the radar. In previous work, signal processing techniques for detecting the presence of unresolved objects and angle-of-arrival estimation for unresolved targets have been developed for monopulse radars. In this paper, these techniques are reviewed and extended. Techniques for detecting the presence of unresolved objects are treated for the case of idealized resolution, in which all of the energy for a target is returned in a single range resolution sample or cell. The approaches work solely on monopulse angle statistics and rely on idealized range resolution. The requirement for idealized range resolution is relaxed by using joint statistics with adjacent matched filter returns. The AOA estimation and detection of the presence of unresolved objects for non-ideal resolution are then addressed. The performances are demonstrated using a high fidelity software simulation tool for target tracking.