[teqc] Single avg position (cart or geo) as output?

Lou Estey lou at unavco.org
Wed Nov 30 20:58:40 MST 2005


Jim's comments are right on target.  (More like two bits worth. ;)

Someday, maybe, the point positioning might be upgraded to do all the
parts for a better position, including even reading SP3 files.  But at
the moment there really isn't much motivation to do that, since there are
so many on-line processing paths (like auto-gipsy).  And the teqc pp
still does suffice for what it was intended.

--lou

> The point position from teqc is a pretty rough one, I think it just  
> uses (P1+P2)/2 as the pseudo-range observation.  It is really only  
> meant as a rough estimate to make sure there were no blunders (i.e.  the 
> data is from another site than expected).  Use the +pos option if  you 
> want a quick and dirty a priori -- +ap will average positions, it  may 
> be a little better, but I still would not trust it that much.   Use the 
> eep options if you suspect that there are multiple  occupations (stop 
> and go) or that the data is actually kinematic.
> 
> If you want a good a priori, then you should use something like  CODSPP 
> (Bernese lingo) to generate a least squares estimate for a  single 
> position over the entire occupation.  And if you can use IGS  orbits and 
> clocks, you should get a position to a few decimeters.   The a priori 
> from TEQC +pos would be just fine for this sort of  estimate.
> 
> My 2 cents.
> Jim
> 
> On Nov 30, 2005, at 5:38 PM, Andrew Miner wrote:
> 
>> Lou (et al.)--
>>
>> Now I see that in addition to the +ap flag there are also some +eep
>> ("every epoch position") flags. Used in various combinations, +pos,  +ap,
>> and +eep yield a variety of positions, while +eepx and +eepg seem  to be
>> meant to be used alone to generate lists of epochs with positions.
>>
>> (See attached)
>>
>> Any comments on the different results or recommendation of a flags to
>> generate a maximally accurate position to use as initial input for
>> processing?
>>
>> On Thu, 2005-08-18 at 13:31 -0600, Lou Estey wrote:
>>
>>> Steve's suggestion is AOK, but there are some other things
>>> that might be of interest.  Michael was asking for a mean position,
>>> and normally teqc just turns the last point position it
>>> determined.  There is an option (that I haven't tested in
>>> years) "+ap" which is supposed to report the average point
>>> position, i.e. include this option when doing +qc and the
>>> lines that Steven pointed out should have the mean position
>>> (which is still a low-precision point position).  But, if
>>> you just want some idea of the position ASAP, do a +qc as
>>> Steven suggested but also include "+pos", which should
>>> terminate teqc and report a low-precision point position (same
>>> format as below) for the antenna as soon as one is determined.
>>>
>>> To summarize:
>>>
>>> +qc -nav RINEX_NAV      : qc with last point position
>>> +qc -nav RINEX_NAV +ap  : qc with average (mean) point position
>>> +qc -nav RINEX_NAV +pos : first point position & terminate
>>>
>>> hth,
>>> --lou
>>>
>>> Mullins, Steven wrote:
>>>
>>>> Michael,
>>>>
>>>> A standard TEQC summary contains the following lines:
>>>>
>>>>   antenna WGS 84 (xyz)  : 644013.2777 -5069344.4809 3804951.2706 (m)
>>>>   antenna WGS 84 (geo)  : N  36 deg 51' 20.62"  W  82 deg 45' 35.59"
>>>>   antenna WGS 84 (geo)  :   36.855728 deg   277.240114 deg
>>>>           WGS 84 height : 595.1376 m
>>>> |qc - header| position  : 36 m
>>>>
>>>> just run TEQC +qc and give a nav and obs file.
>>>>
>>>> Steve
>>>>
>>>> -----Original Message-----
>>>> From: teqc-bounces at ls.unavco.org [mailto:teqc- bounces at ls.unavco.org]On
>>>> Behalf Of Michael Scharber
>>>> Sent: Wednesday, August 17, 2005 2:36 AM
>>>> To: teqc at unavco.org
>>>> Subject: [teqc] Single avg position (cart or geo) as output?
>>>>
>>>>
>>>> Hi There,
>>>>
>>>> Can someone point me to, or show me, how one can use teqc to  produce a
>>>> simple mean position (cartesian or geographic) from a single  input 
>>>> raw or
>>>> RINEX GPS data file.....based on the data, of course, not header
>>>> information.  Position can be low precision - I don't care.
>>>>
>>>> Any advice would be greatly appreciated.
>>>>
>>>> Thanks,
>>>>
>>>> Michael
>>>>
>>>> ps. By "produce" I mean someone spat out to stderr or stdout that  
>>>> can be
>>>> captured by another program.
>>>>
>>>> *******************************************************
>>>>            Michael Scharber
>>>>      Scripps Institution of Oceanography
>>>>      Institute of Geophysics and Planetary Physics
>>>>      8785 Biological Grade
>>>>      IGPP Room 4212
>>>>      La Jolla, CA 92037
>>>>
>>>>          mscharber at gpsmail.ucsd.edu
>>>>      (858)534-1750
>>>> *******************************************************
>>>
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