[jedi_erdi]

Hi,
I want to use RTCM correction data to get corrected position of GPS rover. There are different message types in RTCM data. As i know types 1, 2, 9 and 21 are related with DGPS correction data. I want to know the procedure to get the corrected position using that RTCM messages, e.g. what meassge type(s)should be used, what exactly shoulşd be done wit the correction data, is there some document tells about that?

[typer]

There is already free software that can do this for you, look at rtklib and gogps java.

If you want to do this yourself, you need the rtcm specification from rtcm.org or look at code that implements the protocol like in gpsd gpsd.sourcearchive.com/documentation/2.36/rtcm_8h-source.html.

Then you need to write the algorithms yourself. If you need a good introduction to gps and dgps, look at the documents listed under gps on uio.no/studier/emner/matnat/geofag/GEG2210/v10/pensumliste.xml. Also, check out the sources listed at the end of the document "GPS Enhancements".