Crystal gravfield trap

A crystal gravfield trap (CGT) is a rare and expensive sensor that uses a synthetic crystal grid to detect and identify fluctuations in the local gravity field. They can be blocked by the presence of mass, not being able to detect a ship on the far side of a planet due to its mass.

CGTs were the only sensor that could reliably detect a ship with an active cloaking device. When Grand Admiral Thrawn blockaded Coruscant with a number of cloaked asteroids, locating them became a top priority. The New Republic did not possess any CGTs, and so was required to attempt to steal one from Bilbringi. Garm Bel Iblis had had one at some point, but lost it.