We have an unexpected problem....

We have an unexpected problem...

Think back to 21 August 1999 at 0 UTC, the world experienced
its first GPS Week Number Rollover... at the time Trimble was
recommending for the Scoutmaster...

"Trimble recommends that users who wish to navigate during the GPS
week rollover period reset the receiver prior to operation, and plan
on waiting at least 30 minutes before using the system for
navigation. This will give the system time to collect a full, new
almanac and will minimize navigation problems thereafter.

A reset can be accomplished by performing the following actions:
Place the unit on a flat surface.
Turn the unit off.
Press the following 3 keys:
Down Arrow
Up Arrow
Return
Turn the unit on while holding down these 3 keys.
The display should show this message after the copyright message:
Memory wiped
Turn the unit off.

The ScoutMaster may now be used for normal navigation. Allow 30
minutes for almanac collection and satellite acquisition before use."

I found on that fateful night that, by just turning the unit on without
erasing the memory, the Scoutmaster GPS receiver at first tried to search
for the wrong SVs, and eventually started checking for all of them. Once
it found one... it started loading a new almanac which takes a minimum
of 12.5 minutes. I've never has a problem until a few days ago... the
date is reading March of 1987. And I'm not the only one noticing this
problem!

Suggestions and comments are welcome.

-Sam Wormley

(snip)


Some sort of rollover in the GPSr itself? Or an internal software issue?

Sam Wormley wrote:


Sam,
I have a Quest II in the car and it is showing the correct date & time.
Very quick acquisition also.

nitespark wrote:

I don't doubt that most GPSRs have the correct date and time... All
my other Trimble receivers do... I'm trying to thing what event in the
last month might have confused the Trimble Scoutmaster's algorithm...
at what might be a solution.

Sam Wormley wrote:

FWIW, I got my trusty Garmin GPS V out and dusted it off. Been awhile
since I turned it on and it seem as through it took a bit longer to
acquire, once it did, the clock and date were right on. Your message
piqued my curiosity. It would seem there is some anomaly specific to
your Trimble.