Since INS is subject to "drift," limiting its accuracy, the nav/attack system periodically updates the aircraft's position based on external radio beacons (such as TACAN) or (since the 1990s) GPS or equivalent satellite navigation system, or using a Doppler radar (although this increases the risk of detection).
Radar : BEL 1xDecca 1245 for navigation; BEL 1xDecca 2459 for surface search TACAN; BEL FT13-s/m
The sensor suite fitted to each ship is made up of an AN/SPS-48 or AN/SPS-52 air-search radar backed up by an AN/SPS-49 air-search radar, an SPS-67 surface search radar, an AN/URN-25 TACAN system, along with several other radars for navigation and fire control.