Services

This page explains the function of each ARK-OS service.

This collection of services is referred to as ARK-OS and is installed using the ARK-OS repository. The services are installed as systemd user services and follow the XDG Base Directory Specification.

Mavlink Router

The mavlink-router service routes the MAVLink data from the Pi USB port /dev/ttyACM0 to user defined UDP endpoints. The Pi USB port is connected directly to the Flight Controller USB and is capable of 3Mbps.

The Pi Micro-USB is muxed with the Flight controller USB. The Flight Controller USB connection will not work while the Micro-USB is connected.

The configuration can be edited in the ARK-UI. The default configuration is found here:

https://github.com/ARK-Electronics/ARK-OS/blob/main/platform/pi/main.conf

[General]
# This file contains the mavlink-router configuration

# Disable TCP port
TcpServerPort = 0

[UartEndpoint FCUSB]
Device = /dev/serial/by-id/usb-ARK_ARK_Pi6X.x_0-if00
Baud = 2000000

[UdpEndpoint GCS]
Mode = Server
Address = 0.0.0.0
Port = 14550

[UdpEndpoint logloader]
Mode = Normal
Address = 127.0.0.1
Port = 14551

[UdpEndpoint polaris]
Mode = Normal
Address = 127.0.0.1
Port = 14552

[UdpEndpoint companion_aux]
Mode = Normal
Address = 127.0.0.1
Port = 14569

[UdpEndpoint camera_manager]
Mode = Normal
Address = 127.0.0.1
Port = 14570

[UdpEndpoint ark_ui]
Mode = Normal
Address = 127.0.0.1
Port = 14571

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Logloader

The logloader service automatically downloads the PX4 .ulg flight logs from the Flight Controller SD card after each flight. It will automatically upload the log to a locally hosted Flight Review server and optionally upload to a remotely hosted server.

The configuration can be edited in the ARK-UI. The default configuration is found here:

https://github.com/ARK-Electronics/logloader/blob/main/config.toml

connection_url = "udp://:14551"
local_server = "http://127.0.0.1:5006"
remote_server = "https://review.px4.io"
email = ""
upload_enabled = false
public_logs = false

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Flight Review

The flight-review service is a locally hosted instance of the PX4 Flight Review web application for flight log plotting and analysis. It can be accessed at http://pi6x.local/flight-review/. By default all logs downloaded by logloader will be visible on the local server.

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DDS Agent

The dds-agent service bridges the PX4 uORB pub/sub system to ROS2 topics on the Pi. The bridged topics are defined in PX4 Firmware and can be found here. The dds-agent runs the micro-xrce-dds-agent on the /dev/ttyAMA4 serial port of the Pi. This serial port is connected directly to the Flight Controller Telem2 port and is capable of 3Mbps.

The Flight Controller firmware needs to be configured by setting these parameters:

Parameter	Value	Description
UXRCE_DDS_CFG	102	TELEM 2
SER_TEL2_BAUD	3000000	3000000 8N1

For more information please see the official PX4 docs for UXRCE DDS.

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Hostspot Control

The hotspot-control service configures the Pi as a hotspot if it is unable to connect to a WiFi network after 1 minute from booting. It will create a hotspot with the name pi6x-<serialnumber> with a password of password. Once connected to the hotspot you can go to http://pi6x.local to connect to your local network.

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Polaris

The polaris service provides a client interface to the Point One Polaris RTK Correction Network. This service allows you to receive network RTK corrections over the internet with an active Point One subscription. This allows you to achieve centimeter precision position hold anywhere the network is available.

The configuration can be edited in the ARK-UI. The default configuration is found here:

https://github.com/ARK-Electronics/polaris-client-mavlink/blob/main/config.toml

connection_url = "udp://:14552"
polaris_api_key = "your_api_key_goes_here"

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RTSP Server

The rtsp-server service provides a RTSP Server for live streaming video. The server uses gstreamer and is currently only compatible with CSI cameras, for example /dev/video0. Stay tuned for future plans to support both CSI and USB cameras.

The configuration can be edited in the ARK-UI. The default configuration is found here:

https://github.com/ARK-Electronics/rtsp-server/blob/main/config.toml

path = "camera1"
ip_address = "0.0.0.0"
port = 5600

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ARK UI Backend

The ark-ui-backend service is a REST API backend for the ARK-UI. It provides API endpoints for managing services, querying device information, and updating the Flight Controller firmware.

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