Centipede RTK
Free
Free community casterCasterThe internet server that hands out correction streams. Your rover logs in to it, like tuning into a radio station.Full definition
Free
CentipedeRTK association (France) with volunteer base owners
Good to know: Free, no sign-up
Where it works
4 statesFree volunteer bases. Working US bases on Oct 28, 2026: Millard County UT (HOLM), Parke County IN (ROCKWI), Benton County WA (SSS) and Knox County NE (NIOB). Each one is good for about 6 miles
What it is
FreeA free network of volunteer base stationsBase stationA GNSS receiver sitting still on a known spot. It figures out how wrong the satellite signals are right now and shares that as corrections.Full definition. It started in France and is backed by INRAE, the French national research institute for farming, food and the environment. No sign-up. In the US it only has a few bases, so it only helps if you work within about 6 miles of one. Bases can go offline without warning.
Volunteer bases only Like RTK2GORTK2GOA free public caster where volunteers share their own base stations. Quality varies.Full definition, we rank it below paid networks because nobody promises a base will be on when you need it.
US bases
4 on · 3 offlineWe list Centipede only on the state pages for Indiana, Nebraska, Utah, Washington, where a base was working when we checked. Michigan (TRAK), Montana (SNOM), New York (MRKF) are listed on the map but offline, so we don't count it as an option there. We check again each week.
| State | Base | Where | Status | Last seen |
|---|---|---|---|---|
| Indiana | ROCKWI | Parke County | On | Oct 28, 2026 5:35 AM ET |
| Nebraska | NIOB | Knox County | On | Oct 28, 2026 3:54 AM ET |
| Utah | HOLM | Millard County | On | Oct 28, 2026 12:07 AM ET |
| Washington | SSS | Benton County | On | Oct 28, 2026 6:51 AM ET |
| Michigan | TRAK | Ionia County | Offline | Oct 12, 2026 3:16 AM ET |
| Montana | SNOM | Toole County | Offline | Oct 14, 2026 1:10 AM ET |
| New York | MRKF | Columbia County | Offline | Mar 25, 2026 3:38 PM ET |
Base list read Oct 28, 2026 from the Centipede-RTK map. Map data: Centipede-RTK (ODbL). "Last seen" is the map's last check.
How close you need to be
Centipede says to stay within about 6 miles (10 km) of the base for 1 to 2 cm, which is under 1 inch. It is single-base RTK, so it gets worse the farther you go. A French field test with a good receiver measured about 2 inches at 7 miles and about 4 inches at 32 miles. Those tests were in France, not the US.
Sources: Centipede: host a base; Arvalis field test (Entraid).
Can I use it for paid work?
Yes, as long as you credit "CentipedeRTK" in your reports. You can't resell or pass on the correction stream without written permission. There is no warranty.
Source: Centipede terms of use.
All plans
| Plan | Price | Term |
|---|---|---|
| Free | $0 | No sign-up |
- Contract / terms
- Free, no warranty. Commercial use is OK if you credit 'CentipedeRTK' in your reports. Reselling or redistributing the stream needs written permission.
Coverage
- Where it works
- Free volunteer bases. Working US bases on Oct 28, 2026: Millard County UT (HOLM), Parke County IN (ROCKWI), Benton County WA (SSS) and Knox County NE (NIOB). Each one is good for about 6 miles
- Stations
- 4 working US bases (UT, IN, WA, NE) and 3 listed but offline (NY, MI, MT) on Oct 28, 2026. About 1,289 working bases worldwide, mostly in France.
- Official coverage map
- Open map →
- Needs cell signal?
- Yes: NTRIPNTRIPThe standard way RTK corrections are sent over the internet. Think of it as internet radio for correction data.Full definition needs internet at the roverRoverThe receiver that moves around the job, like a survey pole or a drone. It uses the base's corrections to find its exact spot.Full definition (cell data or a phone hotspot). General rule, not an operator statement.
Connection settings
NTRIP caster
No username or password needed. If your device makes you type one, use centipede / centipede. NEAR and NEAR4 only work if your rover sends its position (NMEANMEAA common text format GPS receivers use to report position and status. GGA is one NMEA message.Full definition GGAGGAA short message your rover sends with its rough location. VRS and nearest-station streams need it to know where you are.Full definition). One device per internet connection (IP address). RTCM3 over NTRIP v1 or v2.
- Receivers that work
- Any NTRIP client that reads RTCM3
Sign-up steps
- Check that your area is covered on the official coverage map.
- Sign up with the operator using the contact on this page.
- Confirm your email if asked, then log in and copy your caster address, port, mount pointMount pointOne specific correction stream on a caster, like one channel on a radio. Each one comes from a certain station or network setup.Full definition, user name and password.
- In your rover's NTRIP client, enter caster crtk.net, port 2101 (or 443 for secure NTRIP 2.0 with TLS), and the mount point you were given (or the one closest to you). Setup help is in the setup guide.
- Go out under open sky and wait for the status to show RTK FIXFixThe best RTK status. The receiver has finished its math and your position is good to about an inch.Full definition before you start measuring.
Fine print
- Support
- docs.centipede-rtk.org
- Last checked
- Oct 28, 2026
States covered4
Not listed by the operator: free trial, discounts, what's included, mountpoints and a few other details. Ask them before you sign up if these matter to you.
No user reliability reports yet. Used it in the field? Tell us how it went.