[teqc] GLONASS navigation error

Lou Estey lou at unavco.org
Wed Jun 18 10:55:51 MDT 2008


hi Uwe,

According to everything I know, and the fact that the other MDB GLONASS
messages in your .m00 file are being decoded by teqc correctly, teqc is
"doing the right thing".  What is odd about the several GLONASS messages
that are in error is that the seconds are (according to the info in the
MDB messages) 59.999 seconds (rounded to "60.0" in the RINEX -- which is
certainly not the way the Leica Spider software treated the seconds.

I'll have to contact Leica to get an explanation.

Thanks for pointing this out.

cheers,
--lou

> maybe it happened already before, but on day 168 it happened for several hours and it was the first
> time we had a closer look, because our Quality check reports the position error.
> 
> I attach the corresponding files.
> 
> The wtzr168a_leica.08g file is rinexed with Leica Spider, the WTZR168A.08G file with teqc.
> 
> 
> Lou Estey schrieb:
>> hi Uwe,
>>
>>> on day 168/2008 we found a difference in the GLONASS navigation
>>> file(s) created by Leica Spider
>>> Rinex Converter and teqc.
>>>
>>> For the ephemeris epoch 16/6/08 00:15:00 the epoch time is recorded
>>> 00:15:60 for all satellites.
>>> This one minute difference causes a huge error in the position of the
>>> satellites resulting in a
>>> wrong position estimate.
>>>
>>> teqc:
>>> 23 08  6 16  0 15 60.0-1.270640641451D-04 3.637978807092D-12
>>> 0.000000000000D+00
>>>     1.060660107422D+04 1.154708862305D-01-9.313225746155D-10
>>> 0.000000000000D+00
>>>    -3.738262207031D+03 3.132190704346D+00 0.000000000000D+00
>>> 3.000000000000D+00
>>>     2.290192138672D+04 4.613704681396D-01-1.862645149231D-09
>>> 0.000000000000D+00
>>> Leica Spider:
>>> 23 08 06 16 00 15  0.0-1.270640641451D-04 3.637978807092D-12
>>> 0.000000000000D+00
>>>     1.060660107422D+04 1.154708862305D-01-9.313225746155D-10
>>> 0.000000000000D+00
>>>    -3.738262207031D+03 3.132190704346D+00 0.000000000000D+00
>>> 3.000000000000D+00
>>>     2.290192138672D+04 4.613704681396D-01-1.862645149231D-09
>>> 0.000000000000D+00
>>> Because of the size, i do not want to attach the corresponding files.
>> That's a pretty interesting difference.  This just occurs on the one day?
>> If you still have the raw Leica data file, send that direct to me and
>> I'll try to figure out what's up.
>>
>> 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
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


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