I would like to explain my situation.
- I have a GNSS receiver, which outputs me NMEA data (read below).
- I receive RTCM data via NTRIP from a caster.
- I would like to correct my GPS position with centimeter-accuracy.
- I do not want to use factory-made GNSS devices which perform this correction on their own.
I know (from other questions on GIS_STACKEXCHANGE) that with only NMEA data I cannot perform any such correction. So I need to buy a GNSS receiver which gives me raw data (is it right?).
Now some questions:
- Do I really need these raw data?
- Which kind of data need I own? Ephemeris? Pseudoranges? What else?
- Do I need to get these same data from the caster? I studied the format and I got that there are several message codes each of one refers to a particular kind of data. Which message need I look to?