A Two Step Adaptive Interference Nulling Algorithm For Use With Airborne Sensor Arrays

In airborne radar systems, both jamming and ground clutter interference can be suppressed by coherently processing multiple time samples of the array output using adaptive interference nulling techniques. This space-time nulling problem may present special difficulties with regard to the availability of sufficient samples for adaptive training. The subject of this paper is an algorithm which nulls jamming and then clutter in two separate stages. The clutter is nulled in a signal subspace of reduced dimension. This approach makes the best use of the available training data, and maintains nulling degrees of freedom where they are most needed. Performance is illustrated with data obtained from Lincoln Laboratory's Mountaintop radar system.