Open source repositories tagged with #uav, ranked by health score.
PX4 Autopilot Software
ArduPlane, ArduCopter, ArduRover, ArduSub source
Cross-platform ground control station for drones (Android, iOS, Mac OS, Linux, Windows)
DroneBridge for ESP32. A secure & transparent telemetry link with support for WiFi and ESP-NOW. Supporting MAVLink, MSP, LTM or any other protocol
