False Alarm Rejection (FAR) Techniques for Missile Warning Systems (MWSs)

False alarms are the primary technical issue with nearly every passive target detection system ever developed, including missile warning systems. This problem prevents these systems from being used to their full potential. The three conventional classes of discrimination algorithms, spatial, spectral, and temporal, have been pressed nearly to their potential limits. DRA developed a more advanced background cancellation algorithm called P-Score Passive Moving Target Detection (PMTD), which is more robust in the presence of noise and less subject to numerical errors than previously tested background cancellation techniques. At the same time, DRA has been studying mixed mode active/passive sensor systems for reducing false alarms. This involves adding a low-cost, optically steerable laser device pointed to the angular bearing of a track and used to confirm target presence and measure its range. Until recently, this was not practical because such a laser device would require a fine tracker system and a very precise gimbal housing. The optimal solution to the false alarm problem combines advanced a background cancellation algorithm with an optional active element to confirm tracks are not false alarms.