Three Dimensional Chaff Simulator

In the field of training and simulation techniques there has long been a need for a device which could be used to effectively expose radar operators to the effects of jamming caused by chaff. Chaff consists of strips of metal which are dispensed from aircraft either by ejection or by a series of drops. Each bundle of chaff contains thousands of these metal strips, cut in various lengths to act as reflectors to a variety of radar frequencies. Chaff is generally dispensed in the area between a radar site and the group of aircraft to be shielded from the radar site. Once the chaff is released normal air currents and gravity cause the chaff to disperse and drift. The radar interference effects can last as long as 30 minutes. A chaff simulator was developed to realistically provide video inputs to operational radar equipment for the purpose of exposing radar operators to this type of jamming. The physical nature of this type of jamming necessitates the use of a three dimensional simulation concept which effectively takes into account the azimuth and elevation beam widths of the radar antenna. A hybrid digital/analog simulator has been developed which provides a realistic radar presentation including the effects of wind, gravity, radar range, scintillation, and antenna pattern. The system is divided into several building blocks, including a target motion generator, the electronic chaff dispenser unit, the chaff position memory unit, the analog computer, the radar simulator, and the video processor.