[teqc] GLONASS navigation error

Terry Nygaard tnygaard at sbcglobal.net
Thu Jun 19 19:56:53 MDT 2008


Lou,

Could I get a new copy of teqc for windows?  We have Leica 1200 GPS and
GX1230 GPS receivers.

Thanks,
Terry

-----Original Message-----
From: teqc-bounces at ls.unavco.org [mailto:teqc-bounces at ls.unavco.org] On
Behalf Of Lou Estey
Sent: Thursday, June 19, 2008 11:47 AM
To: teqc support
Subject: Re: [teqc] GLONASS navigation error

hi Uwe and others using teqc for Leica GLONASS work:

> Well, teqc _isn't_ "doing the right thing" when there are these types of
non-integer
> seconds in nav time tags.  Going back to the teqc vs. Spider translations:
> 
> 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
> 
> The correct time for these messages (using the full resolution in the MDB
records)
> is actually 2008 June 16 00:14:59.999, which the RINEX format can't
represent,
> so the Spider software rounds this to 00:15:00.0.

I've made three changes to check for reading of Leica MDB record 141 and LB2
0xd1
(for GLONASS nav messages); see
http://facility.unavco.org/software/teqc/log.html

1) the math for computing the minutes is now correct if the seconds is
non-integer,

2) the seconds are rounded to the nearest 0.1 second for better
representation in
the RINEX format (see ftp://ftp.unibe.ch/aiub/rinex/rinex211.txt -- Table
A11),

3) if rounding was necessary (and therefore the internal Leica
representation of
the messages times are different from what will be shown in the RINEX), then
a
warning message will be printed (unless -warn or +quiet is being used to
suppress
all warning messages.

With the new code, translation of the file with the above MDB record 141
would
now yield ...

[to stderr]
! Warning ! GLONASS nav message for slot #23 reported to be for 2008 Jun 16
00:14:59.999
         ... being modified to be for 2008 Jun 16 00:15:00.000

[in the teqc-produced GLONASS nav file]
23 08  6 16  0 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

If anyone needs a teqc executable with this correction immediately, please
let
me know.  If there are quite a few requests, I'll try to instead do a full
teqc
release of all builds.

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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