Term given to all Satellite Navigation devices designed for driving.
They are often lost, confused, incorrect and suggesting the user make a U-turn when possible. Examples include directing the user to turn left into a river, against traffic in a one-way system or directing HGVs down single-lane country roads, which has led to a new road sign being created to warn drivers to ignore their sat-nav.
Sat-Nav: "After 200 yards, turn right"
Passenger: "Dude, will you turn off your Shat-Nav, it's directing you into that river!"