A beacon system can easily be applied to recognize the registered drone information since the beacon can be worked as a sort of IoT device. But most of the beacon device can work in a short-range, the control center has lots of troubles to receive the beacon signal in it's out of range. In this study, we designed the drone IFF and tracking algorithm that can track the current position and the flight route of the target drone through the beacon information and the GPS positioning data from the approached relay drone in the beacon range of the target drone. The relay drone has the beacon receiver and GPS sensor and approaches to the target drone to receive the beacon signal. If the relay drone receives the beacon signal in a beacon range of the target drone, the relay drone checks the beacon information and its flight data and transmits it to the control center. To enhance the precision of the algorithm, the relay drone checks more than two different check positions at the critical distance from the inflight target drone. The drone IFF and tracking algorithm can calculate the current position and flight route of the target drone through the two or more GPS data and flight data at the check positions from the relay drone. Since the relay drone flies heading to the inflight target drone, the precision of the drone IFF and tracking algorithm could be fluctuated according to the critical distance and the number of check positions. The experimental results with the DJI Phantom 4 Pro showed the precision of the algorithm is proportional to the product of the critical distance and flight speed and has over 92% with two check positions.
Relay drone, IFF, Beacon, Flight tracking algorithm