4 ms·
Towers do use GPS to sync clocks and typically they also have rubidium clocks so that they can last a considerable time without GPS. Why feed and wait for your
by jjoonathan 8y ago
Towers do use GPS to sync clocks and typically they also have rubidium clocks so that they can last a considerable time without GPS. Why feed and wait for your hungry hippo GPS chip when you can do almost as good (in an absolute sense) or better (in a relative sense) by just observing tower timestamps?
- jhayward 8y agoTo be more complete and precise, they use GPS to condition a rubidium clock. For several reasons it isn't a good idea to take timing directly from GPS without a highly stable local oscillator if you are using the output over long or continuous periods.
- dfox 8y agoAnd to be even more precise in the pre-CAE days the main source for disciplining was SDH/SONET clock of the network interfaces. It is higher stratum clock source than GPS, but as the frequency is higher it ends in more accurate PLL lock.