I still want to see someone slap an airplane grade INS suite into a car and load it up with some maps to see how far it can go without relying on GPS lol.
Not that it would functionally change much, but I find it annoying only self driving cars are still using dedicated navigation setups.
Google Maps has an aneurysm if you're not going above 5mph even though the accelerometer really should have made this a non problem. Its even more dumb to be using your tiny phone receiver for vehicle navigation. GMaps still has to wait until you're past a spot before finally deciding where you actually are.
I like the INS approach, but couple that with cameras to correct for random walk error (this is much like our eyes correcting for our inner ear.)
I think the issue with Google maps requiring GPS differentials for getting your trajectory has mostly to do with it being agnostic of your phone's orientation while moving.
Navigation is not the biggest challenge with self driving.
Obstacle avoidance in an intelligent manner is the bigger problem to solve.
If you want people to trust your self driving solution, it has to be able to account for other vehicles, pedestrians, cyclists, wildlife, trains, fog, blowing snow, potholes, and a myriad of other things that can't be predicted in advance nor be plotted on a map.