Post by deralfromusa on Sept 24, 2007 18:40:09 GMT -5
There seems to be two competing methodologies in the USA.
Proximity and Virtual.
PROXIMITY- I'll call the first just a plain distance network. You dial in and get corrections from the closest network station broadcasting their data. Your lat/long compared to the closest set of corrections.
I tend to think this is reliable and the best for short RTK ranges up to about 12k or such. It can remove the IONO and the tropo is not a large amount usually in these ranges.
You get bit by the PPM's when you reach out much farther.
VIRTUAL- The bases that surround you use your lat/long and use several stations to build a base near you (a virtual base). I think this works with larger networks and longer distances from base stations.
I think you can use these up to many more km's with the same reliable results.
This is just not from the math but from practical experience using GPS. It in Oklahoma terms is called "Squishing the error into the middle"