The Gravitic anomaliser was a component of The Doctor's TARDIS that generated a localized field of artificial gravity around the outside of the TARDIS.
The Fourth Doctor used the anomaliser to help a Skonnan ship escape the gravity field of a nascent black hole. (DW:The Horns of Nimon)
The granitic anomaliser was more commonly used to allow the TARDIS to land on a planet with a low centre of gravity. [source needed]