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What is a companion computer?

A companion computer is a small Linux computer (such as a Raspberry Pi or NVIDIA Jetson) mounted on a drone alongside the flight controller. It runs the tasks the flight controller cannot: video encoding, long-range links, cloud connectivity, computer vision, and higher-level autonomy.

THE ROLE

What a companion computer does

A drone has two brains. The flight controller is a real-time board that stabilizes and steers the aircraft, running firmware such as ArduPilot, PX4, Betaflight, or iNav. The companion computer is a general-purpose Linux computer that sits next to it and does everything the flight controller was never meant to: encode and stream HD video, carry a long-range radio link, connect to the cloud over 4G or 5G, run computer-vision models, and execute higher-level autonomy.

The two connect over MAVLink, the open drone messaging protocol. The flight controller flies the aircraft; the companion computer makes it smart. Because the companion computer is a normal Linux machine, its capabilities are software, so they can be updated and extended long after the airframe is built.

THE SIGNAL PATH

How the two brains connect

The companion computer sits above the flight controller, which sits above the motors and sensors. MAVLink over serial joins the top two.

Onboard signal path

Companion ComputeLinux + Drone Agent

AI inferenceH.264 encodeMAVLink proxy

Flight ControllerReal-time autopilot MCU

Sensor fusionPID control loopsMotor output

Motors + ESC4-in-1, 30 A/channel

SensorsIMU, baro, mag, GPS

The companion runs the agent, the vision engine, and the H.264 encoder. The flight MCU runs the autopilot loop and drives the motors. They exchange MAVLink over serial.

COMPARISON

Companion computer vs flight controller

	Flight controller	Companion computer
Job	Stabilize and steer the aircraft	Video, links, cloud, AI, autonomy
Software	Real-time firmware (ArduPilot, PX4, Betaflight, iNav)	General-purpose Linux
Typical hardware	STM32 flight board	Raspberry Pi, NVIDIA Jetson, Rockchip ARM64
Updated by	Firmware flashes	Software, any time
Connects over	Motors and sensors	MAVLink to the flight controller

Job

Flight controllerStabilize and steer the aircraft

Companion computerVideo, links, cloud, AI, autonomy

Software

Flight controllerReal-time firmware (ArduPilot, PX4, Betaflight, iNav)

Companion computerGeneral-purpose Linux

Typical hardware

Flight controllerSTM32 flight board

Companion computerRaspberry Pi, NVIDIA Jetson, Rockchip ARM64

Updated by

Flight controllerFirmware flashes

Companion computerSoftware, any time

Connects over

Flight controllerMotors and sensors

Companion computerMAVLink to the flight controller

ON ALTNAUTICA

How Altnautica uses the companion computer

Altnautica's open-source drone agent runs on the companion computer. One install turns a Raspberry Pi, an NVIDIA Jetson, or a board matching one of its 21 hardware profiles into a full companion computer, connected to the flight controller over MAVLink, with long-range video, cloud fleet connectivity, on-vehicle AI, and a signed extension system.

Drone AgentOnboard agent that turns a Linux companion board into the drone's brainLearn more Flight ComputerAI compute, flight control, video, and 4G LTE on one boardLearn more Vision EngineModel registry, custom model upload, and on-vehicle inferenceLearn more

Turn any board into a companion computer

One install of the open-source drone agent adds video, links, cloud, and AI to your drone.

Explore the Drone Agent