Hello, We have a system in which we normally synchronize computers to GPS time through a couple of receivers. There may also be long time periods when the GPS is not available and the system gets isolated. There is no internet connection to get the time from. When the system is up and running, it is synchronized to an orphan server which we believe will do just fine, as long as the frequency offset NTP has calculated is close enough to the real errors. It seems the oscillators we have are pretty stable through a wide temperature range, so I'm not too worried about that for now.
However, there can also be long down times during which the time is only kept by the real-time clocks backed up by batteries. The frequency error of the RTC is way too much - measured worst case was about 40ppm. If we rule out getting a better RTC, what are the options? Is there a way within NTP to measure the drift of the local RTC? Maybe write a reference clock driver for it, if NTP is that way able to extract useful information from it? Then we could store the time at shutdown and make a correction to it at boot according to the latest measured drift value. Has anyone tried something similar before? _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
