I've used GPS to calibrate my Arduino clock to nearly 1ppm. It's stable and consistent at a given temperature. The calibration process takes about an hour. With GPS you do not need an accurate RTC. Even when you briefly lose the signal. <10ppm.
I've used GPS to calibrate my Arduino clock to nearly 1ppm. It's stable and consistent at a given temperature. The calibration process takes about an hour. With GPS you do not need an accurate RTC. Even when you briefly lose the signal. <10ppm.