Vehicles produce their own types of signature as do helicopters.
While the operator normally classifies the signatures by listening to an audio channel, it is advantageous to perform the classification automatically. Using our own CW Radar gun, LRDC personnel have participated in trials where there have been various vehicles and have a large collection of radar signatures. We recently conducted trials involving three civilian helicopters to study their classification through the returns from their main rotors. A line drawing of a Robinson R22 is shown below. The algorithm appears to be quite robust and provides classifications comparable with a human operator under most of the circumstances encountered to date.