It used a vector display and cassette tapes for data storage. It was too early for GPS; instead it invented a process called “augmented dead reckoning” that snapped the car’s position back to the known road grid whenever you made a turn. It was the Etak Navigator, and it launched back in 1985. James Killick explores its history in the ninth installment of his series, “12 Map Happenings that Rocked our World,” with some surprises in how it influenced later GPS-based navigation systems (among other things, Etak eventually ended up in the hands of Tele Atlas). See also this 2015 article in Fast Company.
Previously: Guidestar and GM’s Early Attempts at In-Car Navigation.