A Global Positioning System, (TV: Adrift) or GPS, was a device that determined its user's location and provided navigational directions. Many cars in the 21st century had a GPS system installed. (TV: The Sontaran Stratagem)
Cars with ATMOS installed had a built-in GPS which could not be disabled. The system, at least when set to do so, specifically went against any orders the driver gave it. The Sontarans behind ATMOS were able to use this to control cars into killing their drivers. The GPS always said, "You have reached your final destination," before the death(s) of the driver (and sometimes passengers). When one such ATMOS car was being driven by the Tenth Doctor and Ross Jenkins, the car was driven into the river. The Doctor manipulated it into letting them out by telling it to drive into the river, which the GPS system, as programmed, went against. (TV: The Sontaran Stratagem)
Geoff Bluth was driving in a snowstorm when his GPS failed. He called his hotel for directions, but was abducted by an odd man in a pinstriped suit and bowler hat. (PROSE: Attack of the Snowmen)
When Torchwood Three leader Jack Harkness refused to let Gwen Cooper inquire into the people who were disappearing as a result of the Rift, Ianto Jones secretly gave her a GPS device with coordinates to a hidden location where the missing people were kept. (TV: Adrift)
At one point, the Seventh Doctor owned a motorbike with "improvements", such as automatic transmission and GPS. (AUDIO: LIVE 34)
In a message to the Sixth Doctor, the Eleventh Doctor claimed that the TARDIS had a Galactic Positioning System with the voice of Davros. (AUDIO: Trouble in Paradise)
Ryan Sinclair compared the Thirteenth Doctor using her sonic screwdriver to navigate through a forest on Adamantine to GPS; the Doctor called it "Geo-Positioning Sonic". (PROSE: Molten Heart)