> For the complete documentation index, see [llms.txt](https://docs.arkelectron.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.arkelectron.com/products/gps/ark-g5-rtk-heading-gps/px4-instructions.md). # PX4 Instructions The ARK G5H RTK Heading GPS can be operated as a single-antenna GPS or with two antennas to provide GNSS-derived heading. Start with the [Single GPS Configuration](#single-gps-configuration) below, then add the [Dual Antenna Heading Configuration](#dual-antenna-heading-configuration) if you want heading. ## Single GPS Configuration Connect the ARK G5H RTK Heading GPS to the flight controller's CAN port using a standard 4-pin JST-GH cable. ### Flight Controller Parameters Set the following in *QGroundControl* and reboot the flight controller. #### Required | Parameter | Value | Description | | ------------------------------------------------------------------------------------------------------- | ----- | ----------------------------------------------- | | [UAVCAN\_ENABLE](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_ENABLE) | 2 | Enable DroneCAN with dynamic node allocation | | [UAVCAN\_SUB\_GPS](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_SUB_GPS) | 1 | Subscribe to DroneCAN GPS messages | | [UAVCAN\_SUB\_MAG](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_SUB_MAG) | 1 | Subscribe to DroneCAN magnetometer messages | | [EKF2\_GPS\_CTRL](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#EKF2_GPS_CTRL) | 7 | Enable GPS fusion (lon/lat + alt + 3D velocity) | #### Optional | Parameter | Description | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------ | | [UAVCAN\_SUB\_BARO](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_SUB_BARO) | Set to `1` to subscribe to DroneCAN barometer messages | | [UAVCAN\_SUB\_IMU](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_SUB_IMU) | Set to `1` to subscribe to DroneCAN `RawIMU` messages. | | [EKF2\_GPS\_POS\_X](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#EKF2_GPS_POS_X) / [EKF2\_GPS\_POS\_Y](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#EKF2_GPS_POS_Y) / [EKF2\_GPS\_POS\_Z](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#EKF2_GPS_POS_Z) | GPS offset from the vehicle center of gravity (meters) | ### CAN Node Parameters Set the following on the GPS and reboot the node. CAN node parameters can be configured using either: * [QGroundControl](https://docs.px4.io/main/en/dronecan/#qgc-cannode-parameter-configuration) — each CAN node appears as a separate *Component X* entry under **Vehicle Settings > Parameters**. * The [DroneCAN GUI Tool](/knowledge-base/knowledge-base/dronecan-gui-tool-guide.md). #### Required | Parameter | Value | Description | | ----------------- | ----- | -------------------------------------------- | | `CANNODE_PUB_MAG` | 1 | Publish magnetometer messages on the CAN bus | #### Optional | Parameter | Description | | ------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `CANNODE_TERM` | Set to `1` if this is the last node on the CAN bus | | `CANNODE_PUB_BARO` | Set to `1` to publish barometer messages on the CAN bus | | `CANNODE_PUB_IMU` | Set to `1` to publish `RawIMU` messages on the CAN bus. | | `SEP_OUT_RATE` | Output rate for GNSS data messages: `-1` = OnChange, or `50` / `100` / `200` / `500` ms | | `SEP_PVT_MODE` | Bitmask of allowed PVT modes for Rover operation. Bits: `1` = StandAlone, `2` = DGNSS, `4` = RTKFloat, `8` = RTKFixed. Default `15` (all). The receiver uses the most accurate mode available | | `SEP_RCV_DYN` | Receiver dynamics model: `0` = Static, `1` = Quasistatic, `2` = Pedestrian, `3` = Automotive, `4` = RaceCar, `5` = HeavyMachinery, `6` = UAV (default), `7` = Unlimited | *** ## Dual Antenna Heading Configuration The G5H provides yaw estimation using two GNSS antennas on a single DroneCAN node. The mosaic-G5 P3H module handles the calculation internally and reports the heading over DroneCAN. ### Hardware Setup * Connect the ARK G5H RTK Heading GPS to the flight controller'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) ### Flight Controller Parameters Apply the [Single GPS Configuration](#single-gps-configuration) flight controller parameters above, then change/add the following in *QGroundControl* and reboot the flight controller. #### Required | Parameter | Value | Description | | ------------------------------------------------------------------------------------------------------------ | ----- | ----------------------------------------------------------------------------------------------------------------------------- | | [UAVCAN\_SUB\_GPS\_R](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#UAVCAN_SUB_GPS_R) | 1 | Subscribe to DroneCAN GPS relative (heading) messages | | [EKF2\_GPS\_CTRL](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#EKF2_GPS_CTRL) | 15 | Enable GPS fusion + GPS yaw (lon/lat + alt + 3D velocity + yaw). Overrides the value of `7` from the single GPS configuration | #### Optional | Parameter | Description | | ------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [EKF2\_GPS\_YAW\_OFFSET](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#EKF2_GPS_YAW_OFFSET) | Clockwise rotation in degrees from the vehicle forward axis to the MAIN→ANT2 baseline (e.g. `0` if ANT2 is directly ahead of MAIN, `90` if ANT2 is to the right). Equivalent to the `SEP_OFFS_YAW` node parameter — use one or the other, not both | ### CAN Node Parameters Apply the [Single GPS Configuration](#single-gps-configuration) CAN node parameters above, then add the following on the GPS and reboot the node. #### Required | Parameter | Value | Description | | -------------- | ----- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `SEP_DUAL_ANT` | 3 | Enable dual antenna heading. Bitmask: `1` = Fixed (highest accuracy), `2` = Float (more robust), `3` = Fixed + Float (default, recommended — receiver uses best available) | #### Optional | Parameter | Description | | ---------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `SEP_OFFS_YAW` | Clockwise rotation in degrees from the vehicle forward axis to the MAIN→ANT2 baseline. Range: `-360` to `360`. Equivalent to the `EKF2_GPS_YAW_OFFSET` flight controller parameter — use one or the other, not both | | `SEP_OFFS_PITCH` | Pitch offset in degrees to compensate for vertical mounting differences between MAIN and ANT2. Range: `-90` to `90`. A positive pitch indicates the MAIN antenna is mounted lower than ANT2 | *** ## 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. * **Yaw alignment** — 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](/knowledge-base/knowledge-base/gps-placement.md) guide for mounting best practices, interference sources, and antenna positioning. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. 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