Passive radar

The UK Civil Aviation Authority (CAA) has awarded Airbus Defence and Space a study to examine the feasibility of employing latest radar technology for improved air traffic management.

Airbus Defence and Space has developed a ‘passive radar’ system that does not emit radiation, but analyses radiation reflections from other emitters such as radio and television stations, to detect objects.

This makes detection of the aircraft position easier by measuring differences between the original broadcast signal and signals reflected from aircraft in the air.

A conventional radar uses a rotating antenna, actively sending out radio pulses and detects those that are reflected back from aircraft

However, a passive radar system relies on signals that are already in the air, avoiding creation of additional emissions in populated areas, releasing bandwidth for other uses and addressing the problem of misleading echoes from wind farms.

According to Airbus Defence and Space, this type of system is comparatively cost-effective and reliable, than the current systems in use in civil airports.

Passive radar may also help to free-up spectrum that can be used for an upcoming 5G network.

Airbus Defence and Space has been developing the passive radar system since 2006, and has already demonstrated a working system that can detect ultralight aircraft several kilometres away with accuracies down to 20m, and detect larger aircraft 200km away.


Image: Airbus Defence and Space’s Passive Radar, here shown the demonstrator vehicle, uses available radio signals to locate air traffic. Photo: courtesy of Airbus Defence and Space.

Defence Technology