XMAVLink

This library includes a mix task that generates code from a MAVLink xml definition files and an application that enables communication with other systems using the MAVLink 1.0 or 2.0 protocol over serial, UDP and TCP connections.

MAVLink is a Micro Air Vehicle communication protocol used by Pixhawk, Ardupilot and other leading autopilot platforms. For more information on MAVLink see https://mavlink.io.

Installation

If available in Hex, the package can be installed by adding xmavlink to your list of dependencies in mix.exs:

def deps do
 [
   {:xmavlink, "~> 0.5.0"}
 ]
end

Current Status

This library is not officially recognised or supported by MAVLink at this time.

Generating MAVLink Dialect Modules

MAVLink message definition files for popular dialects can be found here. To generate an Elixir source file containing the modules we need to speak a MAVLink dialect (for example ardupilotmega):

> mix xmavlink test/input/ardupilotmega.xml lib/apm.ex APM
* creating lib/apm.ex
Generated APM in 'lib/apm.ex'.
>

Configuring the XMAVLink Application

Add XMAVLink.Application with no start arguments to your mix.exs. You need to point the application at the dialect you just generated and list the connections to other vehicles in config.exs:

config :xmavlink, dialect: Common, connections: ["serial:/dev/cu.usbserial-A603KH3Y:57600", "udpout:127.0.0.1:14550", "tcpout:127.0.0.1:5760"]

The above config specifies the Common dialect we generated and connects to a a vehicle on a radio modem, a ground station listening for UDP packets on 14550 and a SITL vehicle listening for TCP connections on 5760. Remember 'out' means client, 'in' means server.

Connection String Formats

XMAVLink supports the following connection string formats:

• Serial: serial:<device_path>:<baud_rate> (e.g., "serial:/dev/ttyUSB0:57600")
• UDP Out (client): udpout:<address>:<port> (e.g., "udpout:192.168.1.100:14550")
• UDP In (server): udpin:<address>:<port> (e.g., "udpin:0.0.0.0:14550")
• TCP Out (client): tcpout:<address>:<port> (e.g., "tcpout:192.168.1.100:5760")
• TCP In (server): tcpin:<address>:<port> (e.g., "tcpin:0.0.0.0:5760")

DNS Hostname Support

As of version 0.4.2, XMAVLink supports DNS hostnames in addition to IP addresses for network connections. This is particularly useful in:

• Kubernetes/Docker environments where services are accessed via DNS names
• Cloud deployments where static IPs may not be available
• Development environments using service discovery

Examples:

config :xmavlink,
  dialect: APM.Dialect,
  connections: [
    # Using DNS hostname
    "udpout:router-service.namespace.svc.cluster.local:14550",
    # Using localhost
    "tcpout:localhost:5760",
    # Traditional IP address (still supported)
    "udpout:192.168.1.100:14551"
  ]

The router will automatically resolve DNS hostnames to IP addresses at startup. If a hostname cannot be resolved, the router will raise an ArgumentError with details about the resolution failure.

Receive MAVLink messages

With the configured MAVLink application running you can subscribe to particular MAVLink messages:

alias XMAVLink.Router, as: MAV

defmodule Echo do
  def run() do
    receive do
      msg ->
        IO.inspect msg
    end
    run()
  end
end

MAV.subscribe source_system: 1, message: APM.Message.Heartbeat
Echo.run()

or send a MAVLink message:

alias XMAVLink.Router, as: MAV
alias Common.Message.RcChannelsOverride

MAV.pack_and_send(
  %RcChannelsOverride{
    target_system: 1,
    target_component: 1,
    chan1_raw: 1500,
    chan2_raw: 1500,
    chan3_raw: 1500,
    chan4_raw: 1500,
    chan5_raw: 1500,
    chan6_raw: 1500,
    chan7_raw: 1500,
    chan8_raw: 1500,
    chan9_raw: 0,
    chan10_raw: 0,
    chan11_raw: 0,
    chan12_raw: 0,
    chan13_raw: 0,
    chan14_raw: 0,
    chan15_raw: 0,
    chan16_raw: 0,
    chan17_raw: 0,
    chan18_raw: 0
  }
)

Router Architecture

The XMAVLink application is to Elixir/Erlang code what MAVProxy is to its Python modules: a router that sits alongside them and gives them access to other MAVLink systems over its connections. Unlike MAVProxy it is not responsible for starting/stopping/scheduling Elixir/Erlang code.

The router is supervised. On a failure the configured connections and previous subscriptions are restored immediately. If a connection fails or is not available at startup the router will attempt to reconnect each second and continue routing frames on the remaining connections. If a subscriber fails it will be automatically unsubscribed and any new subscriber will be responsible for reconnection.

Utilities

As of version 0.5.0, XMAVLink includes utility modules (previously in the separate xmavlink_util package) for performing common MAVLink commands and tasks with remote vehicles. These utilities provide:

• Cache Manager: Automatically caches received messages and parameters from visible MAV systems
• Focus Manager: Manage focus on specific vehicles for streamlined interactive sessions
• Arm/Disarm: Simple functions to arm and disarm vehicles
• Parameter Management: Request and set vehicle parameters
• SITL Support: Forward RC channels for Software-In-The-Loop simulation

See the included .iex.exs file for convenient helper imports to use in IEx sessions, providing an interactive experience similar to MAVProxy.

Roadmap

• Signed MAVLink v2 messages

Source

Copied from https://github.com/beamuav/elixir-mavlink on 2023-01-01.