# ArduPilot Instructions

## Single GPS Configuration

Connect the ARK MOSAIC-X5 RTK GPS to the flight controller's CAN port using a standard 4-pin JST-GH cable.

### Flight Controller Parameters

#### Required

| Parameter         | Value | Description                              |
| ----------------- | ----- | ---------------------------------------- |
| `CAN_P1_DRIVER`   | 1     | Enable CAN port 1 driver                 |
| `CAN_D1_PROTOCOL` | 1     | Set protocol to DroneCAN                 |
| `GPS1_TYPE`       | 9     | DroneCAN                                 |
| `GPS_AUTO_CONFIG` | 1     | Enable auto-config for serial GPSes only |

{% hint style="warning" %}
Do not set `GPS_AUTO_CONFIG` to 2. The `GPS_AUTO_CONFIG=2` setting only works with GPS modules running AP\_Periph firmware (e.g., the ARK RTK GPS). The Mosaic-X5 runs PX4-based cannode firmware and handles its own GPS configuration internally via the `SEP_*` parameters. Setting this to 2 causes ArduPilot to attempt a parameter handshake with the CAN node that fails silently, blocking all GPS data from being processed.
{% endhint %}

Reboot the flight controller. The GPS should appear as a DroneCAN node and begin reporting position data. The on-board magnetometer will appear as an additional DroneCAN compass and can be enabled via the standard `COMPASS_*` parameters.

### 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                       |

***

## Troubleshooting

* **GPS NO FIX with 0 satellites** — if Mission Planner shows "GPS NO FIX" with 0 sats and no position data, but the DroneCAN GUI Tool shows the GPS is publishing valid fix data on the CAN bus, check `GPS_AUTO_CONFIG`. If it is set to 2, change it to 1 and reboot. Setting it to 2 causes ArduPilot to try to auto-configure the CAN node by requesting parameters that the Mosaic-X5 firmware does not expose under the expected names. This handshake never completes, which blocks all GPS data from being used by the flight controller even though the CAN node is broadcasting valid fixes.
* **Compass calibration or configuration issues** — if you are having trouble calibrating or configuring the compasses, reset all `COMPASS_*` parameters back to their defaults and reboot the flight controller. Perform the compass calibration only after the GPS is connected.
* See our [GPS Placement](/knowledge-base/knowledge-base/gps-placement.md) guide for mounting best practices, interference sources, and antenna positioning.


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