Couldn't the device correct using local land marks? A minimal offline map, maybe even just topographic, that shouldn't change too often. "Expected hill was crested 5 meters sooner then expected, update estimated position accordingly".
If you have local land marks then you don't really need dead reckoning at all. Cheap dead reckoning sensors have so much error and drift right now as to be mostly useless for driving. The expensive sensors work but aren't economical for cheap passenger cars.
Here's the system I was talking about. It used dead reckoning and landmarks (turns) to periodically re-calibrate the fix. This was all done with 80s technology.
> Cheap dead reckoning sensors have so much error and drift right now as to be mostly useless for driving.
I don't think anyone's saying that it would be used for the driving part (i.e. car control), just as an option for orienting the car in the wider world beyond its direct perception.
