The navigational realtime relative timespace monitor sensor was a navigational system. Aboard the Galaxy-class starships, there were at least two of these sensors. In 2368, after the computer systems of the USS Enterprise-D were disrupted by a energy wave from a Satarran starship, Geordi La Forge accessed the basic system directories of the Engineering Department. According to the department, the navigational realtime relative timespace monitor sensors were off-line. (TNG: "Conundrum" )