HowdatamovesfromFCtobrowser.

The Flight Controller controls motors, stabilization, GPS and sensors. The companion computer—Raspberry Pi, Radxa, Jetson or another Linux SBC—runs KairOS Drone Agent and does not replace the FC: it adds video, telemetry relay, cloud connectivity, radio, REST APIs and extensions.

On the ground, Mission Control runs in a browser. It can access the FC directly over WebSerial, Drone Agent over LAN, or a remote relay through MQTT/Convex and WebRTC signaling. Ground Agent is added for WFB-ng use cases and turns radio reception into an accessible local web system.

Automatic transport should first search for a LAN path for about four seconds, then move to P2P signaling with a window of about fourteen seconds. These are design intervals: they depend on the network and are not a KairOS SLA.

• The agent sends a companion heartbeat at 1 Hz with MAV_TYPE_ONBOARD_CONTROLLER.
• After an FC heartbeat, it requests attitude, GPS, battery, RC and sensors.
• Stream requests repeat approximately every 30 seconds to survive FC reboots or state changes.
• Typical ports: /dev/ttyS0, /dev/ttyUSB0, /dev/ttyACM*; the board profile defines automatic discovery priorities.
• The /run/kairos/mavlink.sock IPC socket carries binary frames to other services.
• Mission Control parses MAVLink v2 with CRC; ArduPilot/PX4 use MAVLink, while Betaflight/iNav use MSP v1/v2.

Flight Controller UART
        │
        ▼
kairos-mavlink router
  ├─ /run/kairos/mavlink.sock
  ├─ /run/kairos/state.sock
  ├─ WebSocket :8765
  ├─ TCP :5760 / UDP :14550
  └─ optional cloud relay

The nobuffer and low_delay parameters and a small probe size reduce queues, but actual latency depends on capture, encoder, bitrate, FEC, radio, network and browser decoding. KairOS will publish measurements for specific profiles, not one universal number.

The target KairOS Agent publishes MQTT telemetry at about 2 Hz. The MQTT-to-Convex bridge aggregates state with a debounce of about three seconds per device, while the browser receives reactive queries. Commands are written to Convex; agent polling retrieves pending items, converts them to MAVLink and returns an ACK.

Telemetry: FC → Agent → MQTT → bridge → Convex → Mission Control
Commands: Mission Control → Convex queue → Agent poll → MAVLink → FC
Video: Camera → Agent → MQTT SDP → P2P WebRTC → Browser

The profile literal is ground-station. It shares one codebase with Drone Agent but enables different services: reception instead of onboard encoding, and AP/tether/kiosk instead of FC-centered onboarding.