I`m not really familar to the topic RTK/postprocessing and have a few questions. Many thanks in advance for your help.
What do I need for postprocessing coordinates at centimeter accuracy? Did I forgot something in my list?
- GNSS receiver board for rover which saves raw data
- external antenna for rover-receiver
- GNSS base receiver for reference which saves raw data
- Software (e.g. RTKLIB) for postprocessing in office
So the rover and the base must not communicate with each other? Must the rover and the base simultaneously start recording and record at the same frequency?
Many thanks for your help
You've got it basically right.
If you are near a CORS (Continuously Operating Reference Station) that can be your base receiver. There are many networks around the world which provide data for free.
When post processing no data link between the receivers is needed. All data is time tagged and almost all post processing software can interpolate to handle different data rates. RTKLIB can. Of course the data sets must overlap in time, but if one is recorded at, say, 1 Hz and another at 5 Hz that won't be a problem.
You need a short baseline (distance between base and rover)
You need a very good quality antenna, one that is designed to reject multipath
Horizontal accuracy is typically twice as good as vertical accuracy. For example, if H=1cm, V=2cm
The quality of a solution will be dependent upon the length of time taken to simultaneously measure conditions at base and rover.
Accuracies are often claimed to be centimeter or even millimeter, but the real accuracy is often less than that claimed.
RTK and post processing are two different ideas. RTK stands for real time kinematic - this is characterized by the ability to determine "fixed solutions" (where ambiguities are resolved) in real time - while in the field. Post processing would generally be a technique to analyze observed data in the office after the fact (not in real time).