Investigation on Electromagnetic Immunity of Unmanned Aerial Vehicles in Electromagnetic Environment

The increasing complexity of the electromagnetic environment poses an increasing risk to unmanned aerial vehicles (UAVs) operating in airspaces subject to adverse electromagnetic effects. This paper investigates the potential electromagnetic interference that UAVs may encounter during flight through the lens of electromagnetic compatibility (EMC), which defines the requirements for the proper operation of UAV electronics. According to existing EMC standards, the immunity threshold for typical commercial drones is 10 V/m. However, European standards for public exposure permit electromagnetic fields and suggest that it is possible for an electromagnetic field of a mobile base station antenna to be as strong as 61 V/m. To assess drone vulnerability to its electromagnetic environment, investigation was conducted in an anechoic chamber, which determined that commercially available drones typically experience uncontrolled descent when subjected to an electric field strength of 30 V/m or higher. The primary coupling path for this interference is through the UAV’s internal cables, as induced parasitic currents perturb the motor control signals. This disruption leads to flight instability as the propellers can no longer be reliably controlled, resulting in flight instabilities. Based on a maximum effective radiated power (ERP) of 40 dBW per sector for a base station antenna, a minimum safe operating distance of 20 m was calculated. Adherence to this safe distance is therefore strongly recommended for any commercial drone operator to avoid EMI-induced flight failure.