Trimble Geoexplorer 1,2 date problems

Anybody else annoyed by the failure of Trimble to properly fix the Y2K
problem with their GeoExplorer GPS units? They claim that the wrong date
doesnt affect processing. This is crap. If you are using Rinex files for
differrential correction then the date is scattered throughout the records.
I am amazed that in litigation crazy US that Trimble have been allowed to
get away with this. Didnt Congress pass a law mandating Y2K fixes?
Roman

Roman Szeremeta wrote:


8 September 2006
http://trl.trimble.com/docushare/dsweb/Get/Document-322744/
http://trl.trimble.com/docushare/dsweb/Get/Document-322744/MGIS_SprtNote_GeoExplorerI&II_IncorrectDate.pdf

Sam, they admit the problem but claim that the wrong dates dont affect
processing. Well that is crap. If you use Rinex files then you are stuffed
because they use dates for matching records!!! There goes your ability to
use differential corrections.
Their excuse for producing incorrect data is that it doesnt matter!!!

http://trl.trimble.com/docushare/dsweb/Get/Document-322744/MGIS_SprtNote_GeoExplorerI&II_IncorrectDate.pdf

Roman Szeremeta wrote:



Because of the GPS Week Number Rollover, it is impossible with the current
navigation message to determine the correct date for more than 1024 weeks
(19.6 years), with out an external date source or an internal clock set by
the user... no matter who is the manufacturer.
http://www.navcen.uscg.gov/gps/geninfo/y2k/gpsweek.htm

I understand your frustration, Roman... and share it. Many manufactures of
data loggers and survey equipment didn't expect some units to be in service
long enough to run into the GPS Week Number Rollover problem.

-Sam




http://trl.trimble.com/docushare/dsweb/Get/Document-322744/MGIS_SprtNote_GeoExplorerI&II_IncorrectDate.pdf

It's worth noting that prior to 21/22 August 1999, ICD-GPS-200 defined
GPS Week No. to increment from 1023 to 0.

IRN-200C-004 (12 April 2000, about 8 months after the rollover)
changed the definition to what is now in para. 6.2.4 in the ICD or IS.

The Coast Guard still has their web page that was posted before the
rollover:

http://www.navcen.uscg.gov/gps/geninfo/y2k/gpsweek.htm

DOT has an older version of ICD-GPS-200C, with no IRNs, posted here:

http://ntl.bts.gov/lib/7000/7100/7163/icd200c.pdf

Paragraph 6.2.4 doesn't exist in that version. So one of the IRNs
from 1 to 3 must have added it.

Peter Dana's post a few weeks before the rollover lists a number of
steps that receiver manufacturers could take to handle the rollover,
and provides some historical information too:

http://www.colorado.edu/geography/gcraft/notes/gps/gpseow.htm

The Risks Digest carried a number of entries on the Week No. rollover
issue, such as these:

http://catless.ncl.ac.uk/Risks/16.49.html#subj4.1

http://catless.ncl.ac.uk/Risks/18.24.html#subj3.1

http://catless.ncl.ac.uk/Risks/19.80.html#subj5.1

http://catless.ncl.ac.uk/Risks/20.07.html#subj12.1

http://catless.ncl.ac.uk/Risks/20.55.html#subj3.1

http://catless.ncl.ac.uk/Risks/20.62.html#subj11.1

Note that the first few items were posted well in advance (5 and 3
years before the rollover, respectively).

None of this helps Roman or others in his situation.

But the history is important. Unfortunately, although not knowing
history dooms us to repeat it, knowing history doesn't guarantee the
opposite outcome.