Just like dead reckoning works today, you start from a known point at known attitude and integrate up accelerations and rotations to keep an up to date position. Whenever you can get a GPS signal you use that to reduce the drift. Cheap systems can do this for seconds, 10k$ buys you 15minutes (MEMS), 100k an hour (laser gyro), everything above is under export restrictions and NDAs so noone will tell you what the state of the art is.

Looks like with these frozen gasses one can build even better sensors, which will make no difference for civilian use because it will be even more expensive than existing systems and also because we wouldn't be allowed to use it.