They claim 10E-7 m/s/s precision, which is is about 60cm of drift in an hour, and up to 375 meters after a day. Obviously this won't work without re-calibratin

They claim 10E-7 m/s/s precision, which is is about 60cm of drift in an hour, and up to 375 meters after a day. Obviously this won't work without re-calibrating to a known location at least a few times per day.