"David Cartwright" wrote in
:

Are you sure? I've got 20-year old watches that still work fine, and
I've had plenty of electronic gadgets that didn't make it past a
couple of years. Simple (Radio Shack stopwatch) is often better.

And cost doesn't imply accuracy, either. My 70-quid Accurist watch
keeps better time than my Breitling Navitimer!

GPS is accurate to nanoseconds. Time difference is how it determines
position, and the time has to be so precise that relativistic effects
caused by the satellite's velocity and lack of gravity have to be
accounted for. GPS is more accurate than any conventional timepiece
you'll ever own. The display is less precise than the actual
timekeeping, though, because displaying the time is far down the list of
priorities. The display is certainly accurate to the second, though, and
it is always accurate, because it is controlled by multiple atomic
clocks.

--
Regards,

Stan

"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." B. Franklin