[teqc] Old Ashtech receivers have stopped working

Joe Sass joe_sass at spectraprecision.com
Wed Dec 7 09:45:58 MST 2016


Hi Lou,

Thank you very much!  Very helpful.

Best Regards,  Joe Sass

On Wed, Dec 7, 2016 at 8:04 AM, Lou Estey <lou at unavco.org> wrote:

> On 07-Dec-16 06:59 AM, Joe Sass wrote:
>
>> Hello Lou,
>>
>
> A few weeks ago, many of our old receivers (Z-Surveyor and LOCUS for
>> example) started collecting raw data with bad time stamps and
>> unprocessable data.  In reading some of the threads and speaking with
>> colleagues, your name was mentioned as possibly understanding what
>> changes have taken place or what cusp has been crossed to cause these
>> failures.
>>
>> Do you have any ideas about this?  I am more curious than worried.  Most
>> of the receivers in question have outlived their discontinuance by
>> more than a decade.
>>
>> Thank you in advance for your insights.
>>
>> --
>>
>> Best Regards,
>>
>> Joe Sass
>> Channel Development Manager, Geospatial
>> 935 Stewart Drive | Sunnyvale, CA 94085
>> joe_sass at spectraprecision.com <mailto:joe_sass at spectraprecision.com>
>>
>
> hi Joe,
>
> Here's what I know:
>
> I first heard about week problems with the Ashtech Locus last week when a
> user reported
> that a set of them were recording the date to be the week of 13 Apr 1997.
>
> Last week was GPS week 1925 and 1925 - 1024 = 901, which was the week of
> 13 Apr 1997.
>
> This situation is very much like the same thing the happened to two other
> sets of receivers
> this year; the problems with those receivers (below) started on Sunday
> right after the
> end-of-week rollover.
>
> The first was when Trimble 4700s (and maybe a few of older Trimble
> models?) started
> recording the week wrong by -1024 weeks starting on 14 Feb 2016.
>
> The second was when Ashtech Z-12s and variants started reporting the week
> wrong by -1024 weeks
> starting on 6 Nov 2016.  (see http://postal.unavco.org/piper
> mail/teqc/2016/002185.html)
>
> Now you've included the Z-surveyor (which I believe is related to the
> Z-12, at least
> roughly the same vintage).
>
> The commonality is that these are all older receivers with, essentially,
> unsupported firmware.
>
> I've been told by teqc users (engineers here at UNAVCO and other users)
> that at least
> with raw data from the Trimble 4700s and the Ashtech Z-12s that if you use
> the '-week' option
> with the correct GPS week to read the raw data, using a week value for
> when the data are
> actually for (but not based on the file name or what teqc reports using
> '+mds' or '+meta'
> on the raw data from the receiver), then teqc will correctly translate the
> raw data into RINEX.
>
> Hope this helps.
>
> cheers,
> --lou
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Louis H. Estey, Ph.D.              office:  [+001] 303-381-7456
> UNAVCO, 6350 Nautilus Drive           FAX:  [+001] 303-381-7451
> Boulder, CO  80301-5554            e-mail:  lou  unavco.org
>      WWW:  http://www.unavco.org   http://jules.unavco.org
>
> "If the universe is the answer, what is the question?"
>                                                -- Leon Lederman
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>



-- 

Best Regards,

Joe Sass
Channel Development Manager, Geospatial
935 Stewart Drive | Sunnyvale, CA 94085
joe_sass at spectraprecision.com
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