How to connect an RTK rover to an NTRIP caster
Every NTRIP client asks for the same five things: caster address, port, mountpoint, user name and password. Here is where to find each one, how to enter them, and what the common errors mean.
Last reviewed 2026-10-07.
1. Find a base station near you
Open the SurvSupport map, zoom to where you'll work and click the closest marker. The popup shows the mountpoint name, network, format and coordinates. Closer is better: aim for a base within about 20–30 km. You can also browse by country or network.
2. Collect the connection details
- Caster
- Host name of the network, e.g.
rtk2go.com. Shown on each network page. - Port
- Almost always
2101, the registered NTRIP port. - Mountpoint
- The stream name from the map popup or the network's table. It is case-sensitive.
- User / password
- Depends on the network — see free NTRIP casters.
3. Enter them in your NTRIP client
The client is the piece of software that logs in to the caster and passes the corrections to your receiver. Common choices:
- Phone apps such as SW Maps or Lefebure NTRIP Client (Android), which forward corrections to a receiver over Bluetooth or USB.
- u-center for u-blox receivers such as the ZED-F9P (Receiver → NTRIP Client).
- RTKLIB tools (STRSVR, RTKNAVI or
str2str), where an NTRIP source is written asuser:password@host:port/MOUNTPOINT. - Receiver web interfaces such as Emlid Flow / ReachView, and the correction-input settings on most survey controllers.
- Mission Planner for drones, which can inject NTRIP corrections into the flight controller's GPS.
4. Send your position if the stream asks for it
Some mountpoints — network/VRS streams and "nearest base" mountpoints like Centipede's NEAR — need to know where
you are. The client does this by sending an NMEA GGA sentence to the caster. In the source table this is the
NMEA flag (1 = send GGA). Most clients have a "send GGA" or "send position" option; turn it on for these streams.
5. Check that you get a fix
Within a few seconds the receiver should report RTK float, then RTK fixed once it has resolved the carrier-phase ambiguities. Fixed means centimetre-level; float is typically decimetre-level. With a good sky view and a nearby base, a fix usually takes well under a minute.
Troubleshooting
| What you see | Likely cause |
|---|---|
| 401 Unauthorized | Wrong or missing user name / password, or the account isn't activated yet. On RTK2Go, the user name must be an email address. |
| You get the source table back instead of data | The mountpoint doesn't exist or is offline. Check the spelling (case matters) and pick another base. |
| Connected, data flowing, but no RTK fix | Base too far away, base not sending the satellite systems your receiver tracks, or no base-position message (RTCM 1005/1006). Try a closer base. |
| Stream stops after a while | Client not sending GGA on a stream that needs it, mobile data dropping, or a per-IP connection limit on the caster. |
| Fixed, but positions are offset by a constant amount | The base's published coordinates are wrong or in a different datum. Common with community bases; check against a known point. |
Background reading: what NTRIP is and how it works.