The Holybro DroneCAN GPS has an UBLOX M8N or M9N module, BMM150 compass, tri-colored LED indicator. It has the STM32G4 Processor and adopted the DroneCAN protocol for communication, making it more reliable and better in dealing with electromagnetic interference compare to serial connection. It does not occupy any serial port of the flight controller, and different CAN devices can be connected to the same CAN bus via a CAN splitter board.

DroneCAN

DroneCAN is the primary CAN protocol used by the ArduPilot and PX4 projects for communication with CAN peripherals. It is an open protocol with open communication, specification and multiple open implementations.