According to the abstract, this technology achieves a pretty good result over a 4-minute drive without satellite updates. It's not going to get much better than

According to the abstract, this technology achieves a pretty good result over a 4-minute drive without satellite updates. It's not going to get much better than that, because double integration with phone-grade sensors is insanely error-prone, and that fact won't change no matter how much ML you throw at the problem. How many 4-minute drives do your customers take? This is completely useless for your stated use case.