Onboard autonomy
Building an AI research drone: integrating a companion computer with Pixhawk
The hard part of putting a Jetson or a Raspberry Pi on an aircraft is not getting the two computers to talk. It is deciding what each one is allowed to be responsible for, and then making sure the one running experimental code cannot take the other down with it.
Draw the responsibility split before you buy anything
The autopilot keeps everything that has to work for the aircraft to remain flyable: attitude and position control, arming logic, geofence, failsafe behaviour, the RC link and the motor outputs. The companion computer gets the work that is valuable but not flight-critical: camera and sensor processing, detection, mapping, path planning, payload control and data recording.
The test to apply to every function you are about to move across is simple. If the companion computer stops responding mid-flight, what happens? If the answer is that the aircraft falls out of the sky, the split is wrong. A research aircraft should be able to lose its companion computer completely and carry on under the autopilot's own failsafe: hold position, return or land, depending on how you set it up.
This matters more on a research aircraft than on a production one, because the code on the companion computer is the code being developed. It will crash, it will hang, it will consume all available memory at an inconvenient moment. Design for that as something that will happen.
The link: serial for most projects, Ethernet where the data justifies it
The common path is MAVLink over a serial connection between one of the autopilot's telemetry ports and a UART on the companion computer. It is well supported by both PX4 and ArduPilot, and by the standard MAVLink libraries on the companion side. Three details decide whether it works: the port you use and its configured baud rate, the logic level, and flow control.
Logic level is the one that damages hardware. Pixhawk telemetry ports are 3.3 V logic. Connecting them to anything at 5 V without level shifting risks the autopilot, and a level-shifting adapter is cheaper than the controller. Cross the transmit and receive lines, share a ground, and set the same baud rate at both ends.
Set the baud rate and telemetry stream rates yourself. The defaults are tuned for a radio link and are slow for a wired one. If your application needs fast state data (a controller running at tens of hertz, or precise timestamps), serial starts to struggle, and an Ethernet-capable baseboard with a DDS-based interface is worth the extra complexity. Choose that route because the data rate needs it. Sounding more modern is not a reason.
Source: PX4 companion-computer connection · PX4 1.16 Pixhawk Jetson baseboard setupPower: never take the companion computer off the autopilot's rail
This is the most common integration failure and it is entirely avoidable. The regulated supply on a flight controller is sized for the controller and its peripherals. A companion computer under load draws far more, and in spikes, because the current jumps when the processor and its accelerator wake from idle.
Give the companion computer its own regulator from the battery, sized for its peak draw, and join the grounds so the serial link has a common reference. Then check what happens at power-up. A companion computer's surge at boot on a shared supply is a classic cause of a flight controller that resets every time you power up on the bench, and never at any other time.
Two things to add to the electrical drawing. Which loads pass through the power module's current sensor. If the companion computer is fed separately, the autopilot's consumption figure no longer covers the whole aircraft, and your endurance estimate will be wrong. And a set power-up order, if either device needs one, written on the checklist so nobody has to remember it.
Source: Pixhawk Jetson baseboard overview and specification · PX4 companion-computer connectionMounting, vibration and the cooling problem nobody budgets for
Mount the companion computer so its mass is not hanging off the autopilot's vibration isolation. The autopilot is isolated to protect its IMUs; adding a heavy board to that isolated mass changes its resonant behaviour, and the symptom is a position estimate that degrades as the payload grows.
Cooling is the part that gets discovered in flight. A single-board computer running vision software gives off real heat, and an airframe's electronics bay is often a sealed box of still air. A bench test in an open lab at 22 °C tells you nothing about a closed bay in the sun at 38 °C. Thermal throttling gives no warning: the aircraft flies normally and the frame rate halves.
Plan a thermal path deliberately: a heatsink, ducted airflow, or a metal mounting plate conducting into the frame. Then check it under load, in the closed bay, at the temperature you will fly in. Log the processor's temperature and clock speed with your application's frame rate, so throttling shows up in the data and you do not have to guess it from a bad result.
A baseboard that carries both, or two boards and a harness
Because the Pixhawk 6X-class controllers are compute modules on a separate baseboard, one of the baseboard options can carry the companion computer as well. Our shop lists a Jetson baseboard and an RPi CM4 baseboard, both in the group Holybro publishes for the 5X, 6X, 6X-RT and 6X Pro modules.
The integrated route removes the hand-built harness between two separately mounted boards, which is where intermittent faults live, and it fixes the mechanical relationship between the two computers so it cannot be got wrong on reassembly. The cost is that the pairing is now decided: changing the companion computer means changing the baseboard.
The separate route, a Standard Baseboard or Mini Baseboard plus a separately mounted carrier, keeps both choices open and lets you put each board where it suits the airframe. That is usually the right answer while the payload is still being decided, and the integrated route the right answer once it has settled. Either way, the module and the baseboard are two line items on the order.
If the aircraft itself is not yet chosen, the development kit range is a reasonable airframe to start with. Read the kit name carefully, because it names the autopilot and radio included, and a kit alone does not give you a companion computer setup.
Source: Pixhawk Jetson baseboard overview and specification · Pixhawk RPi CM4 baseboard overview · Pixhawk RPi CM4 baseboard connections and portsThe bench-test checklist, before it leaves the ground
Run all of this with the propellers off and the propulsion made safe. Every line is something that has been found on a bench and would have been found in the air instead.
1. Link up. The companion computer receives the autopilot's heartbeat, and the autopilot sees the companion as a connected system. 2. Read and write. Read a parameter and receive the stream rates you configured, at the rate you configured them. 3. Command path. Send whichever offboard or guided command your application uses and confirm the autopilot accepts it and reports the mode it entered.
4. Failure of the companion. Power the companion computer off mid-session and confirm the autopilot behaves as configured, does not reset, and that its logs record the loss. Then stop your application while leaving the power on, and check the same thing. 5. Failure at power-up. Power-cycle the whole aircraft ten times and confirm the flight controller never resets on the companion's boot inrush.
6. Thermal soak. Run the real workload in the closed bay for longer than your intended flight, logging processor temperature and clock, and confirm no throttling. 7. Vibration. With everything mounted as flown, check the autopilot's vibration levels against the flight stack's own guidance before and after adding the companion computer.
8. Record the configuration. Firmware versions on both sides, autopilot parameters changed, baud rate and port, the companion's operating-system image and your application's commit. A result you cannot reproduce because you cannot say what was running is not a result.
What to send with an enquiry
The autopilot model and baseboard, or that you need both selected; the companion computer you intend to use, or the workload if you have not chosen one; the interface you want between them; the battery voltage and the companion's peak current draw; the space available in the electronics bay with a rough sketch; and your operating ambient temperature.
That last one is worth including even though it feels unrelated to a parts list. It is what decides whether the answer is a heatsink or a duct, and it is much cheaper to design in than to discover.
Ways to put a companion computer next to a Pixhawk
All five baseboards below are listed for the same module family, so you can choose freely between them. What separates them is how much of the integration is done for you, and how much freedom you keep.
| Route | Holybro SKU | Companion computer | What you still specify |
|---|---|---|---|
| Jetson baseboard, with case | 11072A | NVIDIA Jetson, on the same board | Jetson module, storage, cooling |
| Jetson baseboard, no case | 11072 | NVIDIA Jetson, on the same board | Enclosure, Jetson module, storage, cooling |
| RPi CM4 baseboard | 18080 | Raspberry Pi CM4, on the same board | CM4 variant (RAM and eMMC), storage, cooling |
| Standard Baseboard V2B | 18125 | Separate, your choice | Companion board, carrier, mounting, harness, power |
| Mini Baseboard | 18074 | Separate, your choice | As above, in less space |
Part numbers and the module family each baseboard serves are from the Holybro price list behind our shop listings. Connector counts, board dimensions, supported Jetson and CM4 variants and thermal guidance change between revisions. Take them from Holybro's documentation for the exact SKU quoted. The autopilot module is a separate line item on every row.
Source: Pixhawk Jetson baseboard overview and specification · Pixhawk Jetson baseboard dimension and weight · Pixhawk RPi CM4 baseboard overview · Pixhawk RPi CM4 baseboard connections and portsWhat each computer is responsible for
Draw this for your own aircraft before you write any code. The line down the middle is a design decision, and the two power paths at the bottom are what stop a crash on one side becoming a crash on the other.
Products discussed
The parts this guide names.
Specifications on each page are the manufacturer's. Confirm the exact variant and document revision before ordering.
Pixhawk Jetson Baseboard (with case)
Autopilot and Jetson on one board, enclosed. SKU 11072A.
RPi CM4 Baseboard
Autopilot and Raspberry Pi CM4 on one board. SKU 18080.
Pixhawk 6X
The compute module these baseboards take. SKU 11073.
Pixhawk Standard Baseboard V2B
Keep the companion computer separate. SKU 18125.
Holybro X650 ARF Kit
650 mm airframe and propulsion; avionics chosen separately.
Development drone kits
Airframes and kits to build a research platform on.
Sources & basis
What this is based on.
- Baseboard part numbers and the Pixhawk module family each one serves, and the development-kit range, as listed in the Vebix Automation shop.
- Pixhawk telemetry ports are 3.3 V logic; confirm the level, pinout and flow-control support for your exact autopilot and baseboard in the manufacturer's documentation before wiring.
- The responsibility split, power arrangement and bench-test checklist are integration guidance drawn from how these builds fail. They are examples to help you plan. They are not results from a Vebix Automation field test, and we make no performance claim for any companion computer.
- PX4 companion-computer connection (accessed 2026-09-07)
- PX4 1.16 Pixhawk Jetson baseboard setup (accessed 2026-09-07)
- Pixhawk Jetson baseboard overview and specification (accessed 2026-09-07)
- Pixhawk RPi CM4 baseboard overview (accessed 2026-09-07)
- Pixhawk RPi CM4 baseboard connections and ports (accessed 2026-09-07)
- Pixhawk Jetson baseboard dimension and weight (accessed 2026-09-07)
Published 7 September 2026. Last revised 7 September 2026. Corrections to sales@
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