Fixed-wing sensing
Choosing an airspeed sensor and pitot tube for a fixed-wing UAV
GPS speed describes motion over the ground; airspeed describes motion through the surrounding air. For a fixed-wing or VTOL project, specify the sensing method, installation and autopilot support together.
Why GPS speed is not the same measurement
NASA's relative-velocity explanation distinguishes airspeed from ground speed through the wind vector. In a simplified straight-line example, a UAV at 20 m/s true airspeed with a 5 m/s headwind travels at 15 m/s over the ground; the same tailwind gives 25 m/s. Crosswinds require vector treatment.
That example explains the difference between measurements; it does not prescribe a flight speed. Define the aircraft's operating envelope through its design and validation process. Do not select an airspeed sensor by copying a ground-speed figure from a previous flight.
Choose a supported sensor interface
The PX4 airspeed guide lists supported sensor families and interfaces, including I2C and DroneCAN options. Use the documentation for the firmware release you intend to install. A pressure sensor appearing in a catalogue is not sufficient evidence that every autopilot firmware supports that exact module.
Holybro's standard digital airspeed range includes MS4525DO, MS5525DSO and AS1318C options with I2C interfaces. Its DLVR module is a separate DroneCAN product. Record the complete model and interface in the enquiry; 'digital airspeed sensor' leaves both decisions unresolved.
Compare the measurement range with the actual mission
Review differential-pressure range, specified error, temperature conditions and update behaviour alongside the expected airspeed envelope. Resolution is one property of the electronics, not a complete measure of installed accuracy. Also check supply requirements, connector pinout and the available controller port.
For an illustrative low-speed research aircraft, ask the integration team to identify the smallest useful change in speed and the temperature range of the trials. Then compare the documented sensor errors at the relevant conditions. This is a more useful selection brief than choosing whichever board lists the most bits.
Specify the pitot assembly, not only the sensor board
A pitot-based installation measures a pressure difference through its pneumatic connections. The pitot location, tubing and static-pressure arrangement therefore belong in the design review. Check for disturbed airflow, potential tubing kinks, leaks and an accessible route for inspection. Follow the airframe and sensor documentation for the final mounting position.
Holybro offers sensor-only and PT40/PT60 combinations. Confirm exactly what is supplied, including the pitot tube, tubing, cable and mounting provisions. If replacing only a board, identify the existing tube and plumbing so compatibility can be checked instead of assuming the entire old installation can be reused.
Plan calibration and fault checks before flight
PX4 documents sensor selection and synthetic airspeed options. Synthetic estimation depends on estimated wind as well as ground speed; it is not a reason to treat GPS speed as a direct airspeed measurement. Configure the intended source and failure behaviour using the applicable firmware guide.
Create a bench record of sensor detection, correct pneumatic connection, zero/calibration completion and saved parameters. Carry out pressure checks only by the manufacturer's approved method. Include tubing inspection and protection from blockage in the operating checklist, and treat a successful bench reading as one stage of aircraft validation.
What an airspeed-sensor quotation should specify
Send the aircraft type, intended flight envelope, controller and firmware, available I2C or CAN connection, supply details, pitot location and required tube/cable lengths. State whether you need a complete assembly or a replacement sensor board.
For university and UAV development teams in India, this brief helps keep prototype and replacement orders consistent. Browse the Holybro sensor catalogue with the installation drawing beside it, and record the selected variant in the bill of materials before ordering.
Sources & basis
What this is based on.
- NASA Glenn: airspeed, ground speed and wind.
- PX4: supported airspeed sensors and source selection. Check the documentation for the installed release.
- Holybro: standard digital airspeed sensors, comparison and package variants.
- Holybro: DroneCAN DLVR airspeed module.
- The wind calculation and procurement examples are illustrative, not aircraft performance limits or reported trials.
Published 5 September 2026. Last revised 5 September 2026. Corrections to sales@
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Selecting sensors for a fixed-wing build?
Send your controller, firmware and installation requirements. Request an airspeed-sensor quotation with the correct interface and pitot option.
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