PX4 Instructions

Find most up to date documentation at https://docs.px4.io/main/en/dronecan/ark_gps.html

Hardware Setup

Wiring

The ARK GPS is connected to the CAN bus using a Pixhawk standard 4 pin JST GH cable. For more information, refer to the CAN Wiring instructions.

Mounting

The recommended mounting orientation is with the connectors on the board pointing towards the back of vehicle.

The sensor can be mounted anywhere on the frame, but you will need to specify its position, relative to vehicle center of gravity, during PX4 configuration.

Firmware Setup

ARK GPS runs the PX4 DroneCAN Firmware. As such, it supports firmware update over the CAN bus and dynamic node allocation.

ARK GPS boards ship with recent firmware pre-installed, but if you want to build and flash the latest firmware yourself see PX4 DroneCAN Firmware > Building the Firmware.

• Firmware target: ark_can-gps_default

• Bootloader target: ark_can-gps_canbootloader

PX4 Configuration

The ARK GPS will not boot if there is no SD card in the flight controller when powered on.

Connect the ARK GPS CAN to the Pixhawk CAN. Once parameters are set the module will be detected on boot and GPS data should arrive at 10Hz. See DroneCAN > Enabling DroneCAN for more detail.

Required Parameters

Set the following in QGroundControl and reboot the autopilot:

Parameter	Value	Description
UAVCAN_ENABLE	2	Enable DroneCAN with dynamic node allocation (use 3 if also driving DroneCAN ESCs)
UAVCAN_SUB_GPS	1	Subscribe to DroneCAN GPS messages
UAVCAN_SUB_MAG	1	Subscribe to DroneCAN magnetometer messages
EKF2_GPS_CTRL	7	Enable GPS fusion (lon/lat + alt + 3D velocity)

Optional Parameters

Parameter	Description
UAVCAN_SUB_BARO	Set to 1 to subscribe to DroneCAN barometer messages
EKF2_GPS_POS_X / EKF2_GPS_POS_Y / EKF2_GPS_POS_Z	ARK GPS offset from the vehicle center of gravity (meters)
CANNODE_TERM	Set to 1 on the ARK GPS via the DroneCAN GUI Tool if this is the last node on the CAN bus
CANNODE_PUB_IMU	Set to 1 on the ARK GPS via the DroneCAN GUI Tool to publish the RawIMU messages on the CAN bus
UAVCAN_SUB_IMU	Set to 1 on the autopilot to subscribe to DroneCAN RawIMU messages. Requires CANNODE_PUB_IMU to also be set on the ARK GPS