GPS receivers are required to have excellent stability (<<1ppm), but not accuracy. The problem of marine chronometry was also about stability and not accuracy.

GPS receivers are required to have excellent stability (<<1ppm), but not accuracy. The problem of marine chronometry was also about stability and not accuracy. After all, if you have a stable but inaccurate clock and can't tune it for some reason, it's straightforward to compensate for the offset when measuring to calculate your position.