A software-defined direct remote identification broadcaster for a fixed-wing maritime rescue UAS

Abstract

Since January 2024, European Union regulations require every drone above 250 g to broadcast a Direct Remote Identification (DRI) signal containing its identity, position, and operator registration. This thesis presents odid-daemon, a pure software implementation of DRI for drones that already carry a Raspberry Pi companion computer with a Bluetooth and Wi-Fi radio. The daemon is written in C and runs as a systemd service. It reads live position and status data from an ArduPilot flight controller over MAVLink, encodes the five EN 4709-002 message types using the opendroneid-core-c reference library, and broadcasts them on Bluetooth 4 Legacy Advertising and Wi-Fi Beacon simultaneously. Dedicated commercial DRI hardware modules such as the Dronetag Mini or BlueMark DB150 are available, but they add mass, cost, and an additional failure mode to platforms that already carry compatible radios. The implementation was evaluated on the Raspberry Pi 400, which shares the BCM43455 radio with the Compute Module 4 used by the Swedish Sea Rescue Society (SSRS). End-to-end reception was confirmed with Drone Scanner, with Location updates at a measured mean of 1.005 s and all secondary message types at ≥ 0.33 Hz, meeting the EN 4709-002 requirements. The system was further validated in a live SSRS flight test.