roaming | AVP_Matt - 10/1/2018 10:02
I'd actually say either merge 6 and 7 or flip-flop. If you merge, I'd add a new #7 that would be an in-field single base system. That would technically be your highest accuracy, and what is generally recommended for installing tile or other dirt work.
And here's where we get into splitting hairs. :-)
I would agree that an in-field single base system (within 2mi of rover, and the closer the better) is typically regarded as providing the highest vertical accuracy available today, and traditionally has also provided the highest horizontal accuracy.
Trimble RTK horizontal accuracy (horizontal, at least) degrades at a rate of 2ppm (2mm per km). If you do the math, at 13km from the base you have introduced 26mm of error, and if you convert to standard units, that's almost exactly an inch of error at 8mi, which is where Trimble's advertised accuracy (sub-inch up to 8mi from the base) comes from. In theory, I think a networked solution should be able to provide better accuracy throughout the network coverage area, because multiple reference stations are involved in calculating positions, error, etc. I also think this should (again, theoretically) apply to vertical accuracy, but I'm not aware of any service provider making that claim (yet).
Then you can talk about whether you're looking at absolute accuracy compared to the earth, or relative accuracy compared to your base. Surveyed vs autobased installations. Etc.
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What are the different levels of gps accuracies?
