> 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-gps/firmware.md).

# Firmware

ARK GPS runs the [PX4 DroneCAN Firmware](https://docs.px4.io/main/en/dronecan/px4_cannode_fw.html). As such, it supports firmware update over the CAN bus and [dynamic node allocation](https://docs.px4.io/main/en/dronecan/#node-id-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](https://docs.px4.io/main/en/dronecan/px4_cannode_fw.html#building-the-firmware).

* Firmware target: `ark_can-gps_default`
* Bootloader target: `ark_can-gps_canbootloader`

Follow the steps for updating the firmware through the flight controller.

{% embed url="<https://docs.px4.io/main/en/dronecan/#firmware-update>" %}

## Updating to AP\_Periph

To run the node with ArduPilot, flash [AP\_Periph](https://ardupilot.org/dev/docs/ap-peripheral-landing-page.html) instead. AP\_Periph does not publish the ARK GPS IMU.

1. Download `AP_Periph.apj` from the [ArduPilot firmware server](https://firmware.ardupilot.org/AP_Periph/stable/ARK_GPS/).
2. Flash it to the node with the [DroneCAN GUI Tool](/knowledge-base/knowledge-base/dronecan-gui-tool-guide.md). An ArduPilot flight controller can act as the CAN adapter.
3. Set the node's `FLASH_BOOTLOADER` parameter to `1` to replace the bootloader with AP\_Periph's, then reboot the node.

A node with no bootloader needs `AP_Periph_with_bl.hex` flashed over SWD; see [Flashing DroneCAN Nodes](/knowledge-base/knowledge-base/st-link-flashing-guide.md#flashing-dronecan-nodes).

## Downloads

* [ARK GPS Firmware](https://downloads.arkelectron.com/firmware/ark_can-gps/latest/application.uavcan.bin)
* [ARK GPS Bootloader](https://downloads.arkelectron.com/firmware/ark_can-gps/latest/bootloader.bin)
* [All releases and SHA-256 checksums](https://downloads.arkelectron.com/firmware/ark_can-gps/)

Node firmware 1.18 and later can rewrite its own CAN bootloader: set `SYS_BL_UPDATE` to `1` on the node. The flight controller logs `bootloader updated`, `bootloader unchanged` or `bootloader update failed`, and the parameter returns to `0`.

## Node Parameters

Set these on the GPS node, then reboot it. Use [QGroundControl](https://docs.px4.io/main/en/dronecan/#qgc-cannode-parameter-configuration), where each CAN node is a separate *Component X* under **Vehicle Settings > Parameters**, or the [DroneCAN GUI Tool](/knowledge-base/knowledge-base/dronecan-gui-tool-guide.md).

| Parameter                                                                                                 | Default | Description                                                                                            |
| --------------------------------------------------------------------------------------------------------- | ------- | ------------------------------------------------------------------------------------------------------ |
| [CANNODE\_TERM](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#CANNODE_TERM)        | 0       | Set to `1` if this is the last node on the CAN bus                                                     |
| `CANNODE_NODE_ID`                                                                                         | 0       | Fixed node ID (1–125). `0` uses dynamic node allocation                                                |
| `CANNODE_PUB_MAG`                                                                                         | 1       | Publish magnetometer data                                                                              |
| `CANNODE_PUB_BAR`                                                                                         | 1       | Publish barometer data                                                                                 |
| [CANNODE\_PUB\_IMU](https://docs.px4.io/main/en/advanced_config/parameter_reference.html#CANNODE_PUB_IMU) | 0       | Set to `1` to publish the `RawIMU` messages on the CAN bus. PX4 also needs `UAVCAN_SUB_IMU` set to `1` |
| `SYS_BL_UPDATE`                                                                                           | 0       | Set to `1` to rewrite the CAN bootloader from the running firmware                                     |

## Release Notes

### v1.18.0.1 - 76e683ea - 2026-10-03

* PX4 v1.18 base
* Fix the IMU not starting after some resets until the next power cycle
* Bootloader update from the running firmware (`SYS_BL_UPDATE`)

### v1.17 - 67ace351 - 2025-11-14

* [Fix M9N output rate](https://github.com/PX4/PX4-GPSDrivers/pull/191)

### v1.16 - e68afe1e - 2025-02-12

* Disable mag bias estimator by default


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