# ArduPilot Instructions

## Single GPS Configuration

Connect the ARK TESEO 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 TESEO runs PX4-based cannode firmware and handles its own GPS configuration internally via the `TESEO_*` 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 IIS2MDC 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                                                                                                                                                                                                                                                                           |
| `TESEO_FWUPD`      | Set to `1` to force the cannode to re-flash the embedded LIV4F firmware on the next boot. The cannode auto-updates the LIV4F whenever the embedded version differs from what is on the GPS chip — this parameter is only needed to force a re-flash without a version change. Auto-cleared back to `0` after a successful update |

***

## Constellation Selection

The Teseo-LIV4F can track up to **four GNSS constellations simultaneously**. Enabling more than four has no effect — pick the four that match your operating region. SBAS does not count toward this limit. Configure these on the GPS using the same method as the [CAN Node Parameters](#can-node-parameters) above.

| Parameter       | Default | Description                                       |
| --------------- | ------- | ------------------------------------------------- |
| `TESEO_GPS`     | 1       | Enable the GPS (USA) constellation                |
| `TESEO_GLONASS` | 1       | Enable the GLONASS (Russia) constellation         |
| `TESEO_GALILEO` | 1       | Enable the Galileo (EU) constellation             |
| `TESEO_BEIDOU`  | 1       | Enable the BeiDou (China) constellation           |
| `TESEO_QZSS`    | 0       | Enable the QZSS (Japan) constellation             |
| `TESEO_IRNSS`   | 0       | Enable the IRNSS / NavIC (India) constellation    |
| `TESEO_SBAS`    | 1       | Enable SBAS (Satellite-Based Augmentation System) |

***

## 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. See the warning above for why.
* **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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