On Tue, Oct 20, 2015 at 4:02 AM, Brian Garrett <garrettbrian1...@gmail.com> wrote: > ... As measured by NTP apps such as Emerald Time and Watchville, millisecond accuracy comparable to the soon-to-be-released Apple Watch was now commonplace, with typical offsets of 5 ms or less, rather than the several seconds of offset typical under the previous release.
Network connected iOS devices not paired with a watch use (s)ntp at large intervals rather than the mobile network or GPS. The offsets appear to be somewhat random -- both positive and negative, large (s) and small (ms). I assume it's related to the environment and the last time the offset was corrected. > Now, with the latest version, iOS 9, the Apple Watch level accuracy previously available to iPhone users has gone away. Once again, your iPhone will be as much as several seconds slow as measured by NTP, unless you force an update to the phone’s clock by opening a GPS app. I checked on an iPad (but presumably that shouldn't matter). My current offset is -1.6 s (fast, and slowly increasing) as measured by Time independent of GPS which I woke with Observatory which uses both NTP (for time) and the GPS (for location). Restarting the iPad causes a step. This compares with +1 to -3 ms on my phone. I'll admit the above is slightly speculative because I haven't checked network traffic yet but I will shortly. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.