Effectiveness of modern weapon systems demands that it is important to distinguish between friends and foes as early as possible. Radar signal based helicopter categorization is a challenging task for all types of radars. Airborne pulse Doppler radar with an appropriate digital signal processing unit has a good potential to perform categorization or even classification, providing that radar parameters are carefully fixed. Moreover, some information about the main rotor parameters of interesting helicopter types must also be known in advance.
The idea of this paper is to present a helicopter categorization method, which is based on estimates of the main rotor blade tip velocity and the time interval between successive main rotor blade flashes. Both incoherent integration and conventional coherent integration play an important role in the new method. Moreover, a new edge detection algorithm is applied to coherently integrated signal. Simulations are performed in order to show the effectiveness of the method.