Worked on early auto navigation systems at Motorola in the early-90s, using differential wheel sensor data from the ABS system for dead-reckoning interpolation

Worked on early auto navigation systems at Motorola in the early-90s, using differential wheel sensor data from the ABS system for dead-reckoning interpolation between fixes from the original SA-active GPS before the full constellation was deployed. This was a hard problem to solve with the technology of that era, and impossible at an economically viable price point. Our map database was on an original Red Book single-speed CD qualified for automotive temperature range. It took minutes to plan a route. Sometimes the technology just isn't ready.