Will these work without satellites?
It is m understanding that they function like very, very precise gyro compasses. They do not require external input once set on course.
Of course, I could be wrong.
Gyro compasses utilize a gyroscopic device that allows the device to maintain heading when bumped or moved. A regular compass loses heading momentarily or even forever in rough weather. This chip is tiny and unlike a gyro compass is usable is say very small drones.