PX4 Instructions

Single GPS Configuration

Connect the ARK G5 RTK GPS to the autopilot's CAN port using a standard 4-pin JST-GH cable. Set the following parameters in QGroundControl:

Parameter	Value	Description
UAVCAN_ENABLE	2	Enable DroneCAN with dynamic node allocation

Reboot the autopilot. The GPS should be detected automatically and begin reporting position data.

Sensor Position Configuration

If the sensor is not centered within the vehicle you will also need to define sensor offsets:

• The parameters EKF2_GPS_POS_X, EKF2_GPS_POS_Y and EKF2_GPS_POS_Z can be set to account for the offset of the ARK G5 RTK GPS from the vehicle center of gravity.

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Dual Antenna Heading Configuration (G5H Only)

Dual antenna heading requires the ARK G5H RTK GPS (with the Septentrio mosaic-G5 P3H module). The standard ARK G5 RTK GPS (P3 module) only supports a single antenna and cannot provide heading.

The G5H provides compass-free yaw estimation using two GNSS antennas on a single DroneCAN node. The mosaic-G5 module handles the moving baseline calculation internally and reports the heading over DroneCAN.

Hardware Setup

• Connect the ARK G5H RTK GPS to the autopilot's CAN port using a standard 4-pin JST-GH cable

• Connect antennas to both the MAIN and ANT2 SMA connectors

• Mount the antennas with a minimum of 30 cm separation (more is better for heading accuracy)

CAN Node Parameter

The SEP_DUAL_ANT parameter must be set on the G5H CAN node to enable dual antenna heading. This can be configured using DroneCAN GUI Tool.

Parameter	Value	Description
SEP_DUAL_ANT	3	Enable Fixed + Float ambiguities (default, recommended)

The parameter is a bitmask with the following options:

Bit	Value	Mode
0	1	Fixed — highest accuracy
1	2	Float — less accurate but more robust
Both	3	Fixed + Float — receiver uses best available

A reboot of the CAN node is required after changing SEP_DUAL_ANT.

Flight Controller Parameters

Set the following parameters in QGroundControl:

Parameter	Value	Description
UAVCAN_ENABLE	2	Enable DroneCAN with dynamic node allocation
UAVCAN_SUB_GPS	1	Subscribe to DroneCAN GPS messages
UAVCAN_SUB_GPS_R	1	Subscribe to DroneCAN GPS relative (heading) messages
EKF2_GPS_YAW_OFFSET	0	Heading offset in degrees between antenna baseline and vehicle forward axis

EKF2_GPS_YAW_OFFSET defines the clockwise rotation from the vehicle forward axis to the baseline from MAIN to ANT2. Set to 0 if ANT2 is directly ahead of MAIN, 90 if ANT2 is to the right, etc. This is equivalent to the SEP_OFFS_YAW node parameter — use one or the other, not both.

Reboot the autopilot after setting these parameters.

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Troubleshooting

• Heading not appearing — verify UAVCAN_SUB_GPS_R is set to 1 and reboot the flight controller.

• Verify antenna separation — ensure a minimum of 30 cm between antennas. Greater separation improves heading accuracy.

• SEP_OFFS_YAW parameter — if the antennas are not aligned along the vehicle's forward axis, set the SEP_OFFS_YAW parameter on the G5H node to the clockwise rotation angle, or set EKF2_GPS_YAW_OFFSET on the flight controller.

• See our GPS Placement guide for mounting best practices, interference sources, and antenna positioning.