Free RTK corrections from your state
About twenty states run a real-time correction network and give the stream away — but read who it's for before you plan around it.
What it is
A state-run network of permanent reference stations (an RTN) that streams live corrections over the internet by NTRIP. Your tractor's receiver logs in, pulls the stream, and gets the same inch a $300 base would give it, without the base.
The numbers
- About twenty states operate a real-time network. The rest do not, and the gap is not predictable from the map — neighbouring states differ.
- Free, where it is free. Where it isn't, commercial correction services run into the hundreds per year.
- The national NGS CORS archive covers the whole country and is not a substitute — it is a post-processing archive. It can tell you with great precision where you *were*. It cannot steer a tractor.
- Community casters exist too: RTK2Go and Centipede are free, volunteer-run networks, genuinely good enough for pass-to-pass work. Centipede is dense in Europe and thinner elsewhere.
- Any correction, from any source, is only good to roughly 35–50 km from the reference station. Coverage on a map means nothing if the nearest station is a county away.
Why it's here
Because it is genuinely free money when it works, and because the distinction between CORS and an RTN is the single most common way people waste a weekend on this subject.
The catch
Many state networks restrict accounts to agencies, licensed surveyors, and contractors doing public work — which a farmer is not. The terms are often vague on the website and specific on the phone, so ask plainly what the terms are, and ask in writing. The free community casters carry a different catch and it is a sharp one: no uptime guarantee and nobody on call. If the one volunteer station near your field goes down in the middle of planting, you are stopped, and there is no one to ring. Every internet-delivered correction also needs working data where the tractor actually is. If any of that worries you — and during planting it should — the $300 base station is the sovereign path, and it never changes its terms.
In the guide
Chapter 4 of the Autofarmation guide. Autofarmation →