Detection of small unmanned vehicles by the speed of rotation of the propeller

The analysis of the detection capabilities of small unmanned aerial vehicles (UAVs) with an effective scattering area of σ ≤ 0.01 m2 by radar stations (radars) in service in many countries of the World is carried out. Since the range of the UAV is limited to a range of 10-30 km, the article provides energy calculations for these ranges. The article evaluates the operation of pulse and narrowband radars in detection mode with the receiver set to the frequency of the rotating propeller of the aircraft. The narrowband mode is implemented by switching the polarization plane of the antenna's radiation pattern, or its radiation pattern, relative to the equi-signal zone. This mode significantly reduces the required radiation power of the transmitter by reducing the bandwidth of the receiver. Calculations of the spectral characteristics of rotating screws are performed, a comparative assessment of the radiated power of radar transmitters when operating in pulsed and narrowband modes is given. For the latter case, a phase-based range measurement method is proposed. The results of experimental studies are presented.