How ADS-B works

Automatic dependent surveillance-broadcast (ADS-B) is a surveillance system that broadcasts the precise location of the aircraft through a digital data link.

ADS-B allows air traffic control and others to see your aircraft making it safer for all airspace users. ADS-B transmitting equipment (ADS-B OUT) broadcasts on 1090MHz.

Data sent through ADS-B

Broadcasts may include:

  • flight Identification (flight number callsign or call sign)
  • ICAO 24-bit aircraft address (globally unique airframe code)
  • precise position (latitude/longitude) based on GPS
  • position integrity/accuracy
  • barometric and geometric altitudes
  • vertical rate (rate of climb/descent)
  • track angle and ground speed (velocity)
  • emergency indication (when emergency code selected)
  • special position identification (when IDENT selected)./li>

Read more about the benefits of ADS-B.

How ADS-B is used and received

ADS-B OUT equipment broadcasts messages up to twice per second.

Dedicated ADS-B ground stations receive the broadcasts and relay information to air traffic controller for precise tracking of the aircraft. Air traffic controllers can use this data to make sure aircraft are separated in controlled airspace.

Other aircraft with ADS-B IN capability. ADS-B IN receiver systems receive information from other ADS-B OUT equipped aircraft in range. Pilots can see the information presented on a cockpit display of traffic information or in the form of sound alerts. This information can improve pilot situational awareness including providing information about potential aircraft-aircraft conflicts.

Australia’s ADS-B receiver network

Australia commissioned the world’s first continent-wide ADS-B receiver network in 2009. The network is important for continuing to provide safe and efficient air traffic services.

There are many ADS-B ground stations located across Australia. Each ground station has a maximum range of more than 250 nautical miles. The ability of a ground station to receive a signal depends on:

  • altitude
  • distance from the site
  • obstructing terrain.

In airspace immediately surrounding each ground station, surveillance coverage extends to near the surface. In areas further away from a ground station, the coverage may only be at certain heights.

You can view maps showing ADS-B coverage on the Airservices website.

Equipping with ADS-B OUT

The flight rules you’re operating under determines if your aircraft requires ADS-B OUT equipment.

Operating under the instrument flight rules (IFR)

All aircraft operating in Australia under the IFR must be fitted with approved ADS-B OUT equipment. This fitment requirement has have been in place since 2017.

Operating under the visual flight rules (VFR)

You don’t need ADS-B OUT equipment if you’re operating under the VFR. There are rare occasions where you can gain authorisation to operate at or above flight level 290. There are transponder fitment requirements that apply to aircraft operated under the VFR.

However, we strongly encourage VFR operators to fit ADS-B technology due to the safety benefits it offers. Any ADS-B OUT equipment must be of an acceptable configuration.

You can find these details under Division 26.16 'Surveillance equipment' of the Part 91 Manual of Standards.

Last updated:
25 Aug 2023
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