Mavlink network

MAVLink is a message based network protocol. Every packet identifies the sender with two fields:

• sysid: the system id. This usually identifies one vehicle, ground station, antenna tracker, camera rig, or other MAVLink node on the network.
• compid: the component id inside that system. For example, one vehicle may use the same sysid for its autopilot, camera, gimbal, and companion computer, while each component uses a different compid.

Together, sysid and compid form the source address of a MAVLink component. Messages that target a specific receiver usually include target_system and target_component fields in the message payload. A ground station can use these fields to send a command to one vehicle, or to one component on that vehicle.

Some MAVLink messages are effectively broadcast. They are sent on the link and any receiver that understands the message may consume them. Heartbeats, position, attitude, and status messages commonly work this way: each component publishes its state, and routers or endpoints forward the packet to other links. Broadcast is also commonly represented by target values of 0, meaning all systems or all components, when the message type has target fields.

In a routed MAVLink network, tools such as mavlink-router forward messages between serial, UDP, and TCP links. The router does not assign vehicle identity; it forwards packets while preserving the sender sysid and compid, so every endpoint can decide whether a message is relevant.

---

Mavlink router

MAVLink Router is a proxy that forwards MAVLink traffic between several endpoints, such as a flight controller, ground control station, simulator, companion computer, or telemetry radio. It lets one MAVLink source be shared by multiple clients and can route traffic across UDP, TCP, and serial links.

more project github

Build static aarch64 musl binary

./mavlink-routerd-glibc-x86_64 -e 127.0.0.1:14550  -p 127.0.0.1:5760

---

Demo: route message using mavlink-router

flowchart LR
    Drone["Drone / Flight Controller"]
    Router["mavlink-router"]
    Operator["GCS: Operator"]
    Supervisor["GCS: Supervisor"]

    Drone <-->|MAVLink| Router
    Router -->|UDP 14550| Operator
    Router -->|UDP 14551| Supervisor

./mavlink-routerd-glibc-x86_64 \
  -e 192.168.1.20:14550 \
  -e 192.168.1.21:14551 \
  /dev/ttyACM0:57600

In this example, /dev/ttyACM0:57600 is the serial MAVLink source from the flight controller. Each -e option adds a UDP endpoint that receives the routed MAVLink stream.

The same route can be written as a mavlink-router config file:

[General]
ReportStats=false

[UartEndpoint flight_controller]
Device=/dev/ttyACM0
Baud=57600

[UdpEndpoint operator_gcs]
Mode=Normal
Address=192.168.1.20
Port=14550

[UdpEndpoint supervisor_gcs]
Mode=Normal
Address=192.168.1.21
Port=14551

./mavlink-routerd-glibc-x86_64 -c main.conf

The config file is split into endpoint sections:

• [General] contains router-wide settings.
• ReportStats=false disables periodic traffic statistics in the router log.
• [UartEndpoint flight_controller] defines a serial MAVLink link named flight_controller.
• Device=/dev/ttyACM0 selects the serial device connected to the flight controller.
• Baud=57600 sets the serial baud rate for that device.
• [UdpEndpoint operator_gcs] and [UdpEndpoint supervisor_gcs] define UDP outputs for two ground stations.
• Mode=Normal makes the UDP endpoint send MAVLink packets to the configured address and port.
• Address=192.168.1.20 and Address=192.168.1.21 are the destination IP addresses for each ground station.
• Port=14550 and Port=14551 are the destination UDP ports.

With this config, MAVLink packets arriving from the flight controller serial port are forwarded to both ground stations over UDP.

Demo: control traffic

Use endpoint filters when the supervisor station is only a monitor. This example sends only heartbeat and GPS position messages to the supervisor endpoint, and drops any MAVLink packets received from that supervisor endpoint before they can be routed back to the flight controller.

[General]
ReportStats=false

[UartEndpoint flight_controller]
Device=/dev/ttyACM0
Baud=57600

[UdpEndpoint operator_gcs]
Mode=Normal
Address=192.168.1.20
Port=14550

[UdpEndpoint supervisor_monitor]
Mode=Normal
Address=192.168.1.21
Port=14551
AllowMsgIdOut=0,24,33
AllowSrcSysIn=0

The supervisor receives:

• 0: HEARTBEAT
• 24: GPS_RAW_INT
• 33: GLOBAL_POSITION_INT

AllowMsgIdOut=0,24,33 is applied only to traffic leaving the router through supervisor_monitor; the operator ground station still receives the full stream. AllowSrcSysIn=0 drops normal MAVLink packets received from the supervisor, because MAVLink source system id 0 is reserved for broadcast targets and should not be used by a real sender. For a passive monitor, you do not need to allow heartbeat from the supervisor. Only allow it if the supervisor should become an active MAVLink participant that the router discovers and routes messages to.