cheap GPS

bmanning@vacation.karoshi.COM writes:

Something to look forward to. :slight_smile:

Any predictions whether this will have more or fewer affects than
NIST setting daylight savings time in the wrong month a few years
ago on WWV/B?

Nothing unexpected - Y2K problem is not the problem of 2000 year (90% of
the cry about Y2K readyness and so on are only a good way to pick up more
money) - the real problem for the real-time devices will b� the scale
limits of the internal _real-time_ counters which count everywhere except
the year 2000; this is the nearest example of such overloading.

Through I did not see anything to worry about - your GPC may be show you
the wrong date, but why it can affect the accuracy at all (except some
short time around the very moment itself).

This is not true. There is things called the catelog and ephemerus, which
are time based and give detailed corrections of the orbital position of
the satellites that GPS derives locaton from. If the receiver does not
handle rollover correctly, it will not correctly return time or position.
Most receivers built since the mid 90s have handles this, and even more of
the precision time sources have handled this, but nothing is perfect. It's
really easy for the manufacturer to test this, but almost impossible for a
user to (you need a GPS simulator.)

The good thing about modern NTP systems is that they don't accept times
that are way off (there was a bad incident of a wacko clock many years
ago) so if the GPS reports a 1980 date, the software would not believe it.
That would mean losing synch with the GPS, but that should not be the end
of time for a reasonalbly configured system.

I'll be watching all my clocks, but a lot of people won't be.


I'm interested in knowing if there are any telcos that
are using a GPS for their ckt timing, and this will cause that timing to
break, and those of us that take "clock source line" from M13's, etc..
will have problems with our channelized ckts (dial, ct3, etc..?)

  Anyone here privy to that type of information, and can
you comment?

  - jared

Quite agree; any global timing will be wrong and it at least affect the
accuracy of positioning.

Through it's just another example of the fact that Y2K is not Y-2000
problem at all; it's a problem of the limited clock counters... Let's
wait until 2038 or (better) 2106 year -:).