[FOSS-GPS] Which settings must I chose to post-process 1/2h known base + station observations

Denis FEURER denis.feurer at ird.fr
Thu Nov 28 02:35:41 PST 2013

Hi Julio,

I thank you a lot for your kind and helpful answer. I'm not very
skilled in GPS and I must post-process my data in order to get precise
coordinates of my local reference points.

I tried to compile the command line tools (which I would like to use,
I'm used to this, I work on ubuntu) but I got an error. Hence I ran the
rtkpost.exe soft (with Wine).

I used the "static" setting and gave the accurate coordinates of the
base, the .obs files of base and station and the .nav file of station.
All other settings (and there are plenty of it) have been left to

Some things puzzle me in the result :
-seen in Google Earth, the base position is 4 meters apart from the
place it is supposed to be at : I guess some error is normal but is
that one OK ? Actually my base point is a national Tunisian geodetic
reference. It has been GPS-observed by the tunisian cartographic
agency, which gave me the precise coordinates.
-the .pos (and hence the .kml) have numerous values : which one must I
choose ? Must I average the best ones ? (the very first value of
the .pos file is 50cm apart the others. It has a Q=2 value. All others
stand in a 1-cm square : quite impressive !)

Many thanks in advance for you kind help,


 On Wed, 27 Nov
2013 09:16:50 -0800 (PST) julio menezes <yjmenezes at yahoo.com.br> wrote:

> Hi Denis.
> you can post-process your static data with rnx2rtpk or rtkpost.
> The occupation time is ok as you have L1+L2 and 5 seconds for this
> condition is ok too. see Manual 2.4.2 page 93/94 and use the options
> for console rnx2rtkp: rnx2rtkp -p 3 -m 15 -f  2 -l lat_base lon_base
> height_base   rover.obs base.obs base.nav you can use sp3 if you like
> but not needed for short static lines.
> i hope it helps.
> regards,
> julio menezes
> Em Quarta-feira, 27 de Novembro de 2013 14:05, Denis FEURER
> <denis.feurer at ird.fr> escreveu: 
> Dear all,
> I acquired L1/L2 GPS data this summer with this setup :
> -1 antenna fixed on a known point and acquiring data during 4 hours
> -another antenna fixed on unknown points and acquiring data during
> 1/2h on each points within this 4-hour period of time
> I have hence 4 points observed during 1/2h and I would like to
> determine their precise position thanks to the GPS data acquired on
> the known point during the same time. All these points (known base and
> unknown stations) are within a circle of less than 5km.
> I know I might have acquired data during less time but I was not sure
> that I would have the known position of the base point at the time I
> did GPS observations.
> What setting am I supposed to choose in the "settings 1" window ?
> Must I use precise clock and ephemeris data and if so how do I manage
> to use it ?
> Thank you very much in advance for your kind and helpful answers,
> Denis
> P.S :
> By the way, with this setup (acquisition for post-processing data), at
> what frequency must I acquire GPS data ? (1s, 5s, 10s, 15s,
> 30s, .... ?) _______________________________________________
> This message is sent to you from FOSS-GPS at lists.osgeo.org mailing
> list. Visit http://lists.osgeo.org/mailman/listinfo/foss-gps to
> manage your subscription For more information, check
> http://wiki.osgeo.org/wiki/FOSS-GPS

More information about the FOSS-GPS mailing list