The objective of the proposed research effort is to identify knowledge representation techniques for the enhancement of signal and information processing. it is proposed that the shortcomings of current signal processing techniques are overcome by incorporating real-time expert systems and tactical terrain information. The shortcomings that are considered include (but are not limited to) vulnerability to jammers, unacceptably high probability of false alarm, and vaious deception techniques such as aerosol absorbers and chaff. The focus of our efforts is the manipulation of objects and events vis-a-vis a tactical terrain database, real-time data fusion from multiple sensors and distributed problem-solving. The appropriate implementation of these concepts will result in the acquisition of appropriately filtered esm information, and secure communication links.