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​NAV CANADA’s air navigation services rely upon the effectiveness and accuracy of the​ surveillance technologies to keep Canadian skies safe and aircraft moving efficiently. The Company uses the following technologies to deliver world-leading service to its customers:

  • Automatic Dependent Surveillance-Broadcast (ADS-B)
  • Multilateration
  • Radar

Automatic Dependent Surveillance-Broadcast

Automatic Dependent Surveillance-Broadcast (ADS-B) is a discrete, near real-time air traffic surveillance system. The system automatically pulls data from aircraft equipped with an ADS-B transponder – requiring no pilot or external input – and regularly broadcasts it for detection by ATM providers and other airspace users. 

Space-based ADS-B

While ADS-B receivers have traditionally been located on the ground, that has changed. ADS-B sensors are now located on low earth orbiting satellites opening the door to global surveillance coverage by providing line-of-sight well beyond the limits of ground-based networks.

Discover more about Space-based ADS-B​

ADS-B Performance Requirements and Mandate​

NAV CANADA will be implementing an ADS-B Out Performance Requirements Mandate within Canadian domestic airspace in a phased approach

Learn more about the requirements and mandate​

Ground-based ADS-B 

Using ground-based ADS-B, our air traffic surveillance covers four million square kilometres of airspace. Prior to using ADS-B service, operators should be familiar with airworthiness and operational requirements outlined in AIP Canada ENR 1.6.3.


Multilateration – Surface Detection

Multilateration (MLAT) provides surveillance using existing transponder technology. It improves situational awareness where radar coverage is not available, supporting complex traffic flow management and safer, more efficient customer operations. MLAT is also used for airport surface surveillance, providing full coverage of runways, taxiways and terminal areas.

Operational requirements for the use of MLAT are outlined in AIP Canada ENR 1.6.4.

Multilateration – Wide Area Multilateration

Wide Area Multilateration (WAM) is a system of ground stations that receive signals from aircraft transponders to determine aircraft position. This information can then be used by an air traffic controller for SSR-equivalent surveillance and separation.


The air navigation system uses radar surveillance for terminal and enroute control. Two types of radar equipment are used. Primary Surveillance Radar (PSR) and Secondary Surveillance Radar (SSR) are installed at airports and collocated.

Primary Surveillance Radar

A PSR locates and displays aircraft position (range and azimuth) based solely on the radio echo.

Secondary Surveillance Radar

An SSR interrogates an aircraft’s transponder, which causes the transponder to send back an identification code or aircraft ‘TAG’. The radar will display the ‘TAG’ and other information returned, along with the position, for the air traffic controller.

Airport Surface Detection Equipment

At selected larger airports, surface aircraft and vehicle traffic are monitored during periods of reduced visibility using Airport Surface Detection Equipment (ASDE) radar. The Ground Controller in the control tower monitors movements of aircraft and vehicles on a map display based on data from a high definition PSR. Runways, taxiways, building outlines and other obstacles are overlaid on the radar display. There are 6 in operation in Canada.​​​​​​