Airborne radars such as AW ACS capable of large area surveillance of aircraft over both land and sea have become a reality in the past few years. Soon to follow are radars capable of large area surveillance of moving ground traffic. Through their ability to accurately report enemy movement and to target individual enemy ground vehicles, these radars will undoubtedly have a large impact on intelligence gathering, resource allocation, command, control and the damage assessment functions. This report describes relationships and trade-offs fundamental in the design of airborne surveillance radars in various operational roles. It describes radar capabilities which can be achieved using modern technology including array antennas, advanced waveforms and advanced signal processing techniques.