# UAV Detection Using Thrust Engine Electromagnetic Spectra
###### Abstract  
Artificial intelligence used in unmanned aerial vehicle (UAV) flight control systems tends to leave UAV control systems without any radio communication emissions, whose signatures in an electromagnetic spectrum (ES) are widely used to detect UAVs. There will be problems in the near future in detecting any dangerous threats associated with UAV swarms, kamikaze unmanned aerial vehicles (UAVs), or any other UAVs with electrically powered thrust engines because of the UAV's flight capabilities in full radio silence mode. This article presents a different approach to the detection of electrically powered multi-rotor UAVs. The main idea is to register the electromagnetic spectrum of the electric thrust engines of the UAV, which varies because of the changing flight conditions. An experiment on a UAV's electric thrust engine-produced electromagnetic spectrum is carried out, presenting the results of the flight-dependent characteristics, which were observedplaces [5]. When fully autonomous flight autopilot systems handle flight without the aid of radio communication or navigation, detecting UAVs becomes much more challenging [6].  
On 5 August 2018, Venezuelan President [PERSON] was attacked by civilian UAVs, including two DJI M600 UAVs carrying C4 explosives [7]. One of the busiest runways at Gatwick Airport closed on 20 December 2018. Some 110,000 passengers were delayed on 760 flights as UAVs repeatedly flew over the airfield. The threat of drones is clearly one of the biggest unsolved security problems in the near future. As a result, the task of detecting UAVs in no-fly zones becomes a difficult but largely unsolved task [8]. Each country has its own no-fly UAV zones for airport security and strategic infrastructure. However, with the development of intelligent UAV control technology, future high-capacity communication links are likely to fail to achieve the desired security. They are likely to become obsolete.  
UAVs that communicate with other devices via radio communication or are controlled by radio communication from other devices could be detected by detecting the radio communication channel. However, UAVs whose control is completely autonomous eliminate this possibility of their detection. For this purpose, alternatives are needed that allow UAVs to be detected in another way.  
The article proposes a unique motor-driven antenna that allows the stepless switching of the resonant frequency for signal tracking and reception.  
In a recent work, the possibility of detecting drones up to 1.5 m using an extremely low frequency range (5-20 kHz) range was demonstrated [9; 10]. Measurement of the magnetic field of the rotating elements of the asynchronous motor and the rotating field of the stator was shown to allow identification of the corresponding frequencies of the motor [11]. The possibility of drone detection using leakage flows from different brushless direct current (BLDC) motors was successfully demonstrated in a low-frequency radio frequency band [12]. A hypothesis has been formulated that, by measuring the spectrum of the engine control signals, we can detect UAV-specific traces in the spectrogram.