Mavlink
MAVLink (Micro Air Vehicle Link) is a lightweight communication protocol used to exchange messages between drones (UAVs), their autopilots, ground control stations, and companion computers
In MAVLink, every message is tagged with two identifiers so the network knows who sent the message and which part of the system it came from:
Mavlink
MAVLink has been deployed in a number of versions:
- MAVLink 1: 0xFE
- MAVLink 2: 0xFD
SYSID (System ID)
A number that identifies the vehicle/system. (1-255) Distinguishes different vehicles on the same MAVLink network (Vehicle ID)
Examples:
- Drone #1 → SYSID = 1
- Drone #2 → SYSID = 2
- Simulator (SITL) → often SYSID = 1 (configurable)
- GCS () = 255
COMPID (Component ID)
A number that identifies a component inside a system. (1-255) Distinguishes subsystems within the same vehicle
Think of it as the process/module ID
Common COMPIDs: - 1 → Autopilot (flight controller) - 190 → Companion computer - 191 → GCS (ground control station) - 200+ → Custom components
Source / Target / Broadcast
In MAVLink, every message has two layers of identity:
1️⃣ Message header → SOURCE - These are set automatically by your MAVLink connection: - source_system (your SYSID) - source_component (your COMPID)
👉 Identifies who is sending the message.
2️⃣ Command fields → TARGET - Certain messages (especially commands) include explicit target fields inside the payload: - target_system - target_component
👉 Identifies who should execute the command.
Example: COMMAND_LONG(76)
Broadcast
- Telemetry → always broadcast
- Queries → sometimes broadcast
- Control commands → never broadcast unless you are 100% sure
Mavlink network
MAVLink “stream” is usually one physical link to connect multiple customer we use tool like mavlink-router