ADS-B transponders for drones

ADS-B (Automatic Dependent Surveillance–Broadcast) lets an aircraft broadcast its GNSS position, altitude, speed and identity, and lets others receive those broadcasts. Transponders reply to secondary surveillance radar interrogations. Together they make the vehicle visible to air traffic control and other airspace users.

Equipment types

• ADS-B Out: transmits the aircraft’s own position. Usually built into a Mode S transponder (1090 MHz extended squitter); in the United States, 978 MHz UAT is also used at lower altitudes.
• ADS-B In receivers: show nearby equipped traffic to the remote pilot or to a detect and avoid system. Light, low-power and common on drones.
• Mode S and Mode C transponders: reply to radar interrogations with identity and altitude.
• Remote ID: a separate, drone-specific broadcast identification required in many countries, sometimes combined in the same device.

Key specifications

• Frequencies: 1090 MHz, 978 MHz UAT or both.
• Transmit power and class, matched to the airspace and operation.
• Certification: TSO (FAA) or ETSO (EASA) approvals, and compliance with DO-260B for ADS-B Out.
• Integrated GNSS source or external one, and its integrity level.
• Size, weight and power: drone units weigh a few tens of grams.
• Interfaces to the autopilot and ground station.

A note on use

Regulators limit how ADS-B Out is used on small drones, to avoid cluttering air traffic displays and the 1090 MHz frequency with many low-altitude transmitters. Check the rules of each country before fitting one.

Manufacturers in the directory

Examples include uAvionix, Sagetech, Garmin and Honeywell Aerospace.