Range-Doppler characteristics of multi-rotor unmanned aerial vehicle in low-frequency passive radar

Passive radar based on Frequency Modulation (FM) Broadcast, Digital Video Broadcasting for Terrestrial (DVB- T), Digital Terrestrial Multimedia Broadcast (DTMB) and other low-frequency signals is of great concern, which can be used for unmanned aerial vehicle (UAV) detection. This paper establishes the echo model of the multi-rotor UAV and analyzes the range-Doppler characteristics with different flight states in the low-frequency passive radar. The results show that the micro- Doppler generated by the rotor in the low frequency is no longer the sinusoidal form, but the discrete frequency point, which produces multiple frequency lines in the range-Doppler image. The conclusion is confirmed by the field experiment, which has reference significance for multi-rotor UAV recognition.