How to set up Trimble with NTRIP corrections

Trimble Access has built-in NTRIP support. This guide walks you through creating a survey style with an internet data link, connecting to an NTRIP server and selecting the right mountpoint — for any Trimble controller and any NTRIP service.

Before you start

Requirements

Trimble controller (TSC3, TSC5, TCU5, TDC600 or similar) with Trimble Access installed
Trimble GNSS receiver (R10, R12, R780, SPS986 or similar) connected via Bluetooth
NTRIP credentials: host address, port, mountpoint, username and password
Internet connection on the controller (SIM card, Wi-Fi or tethered phone)
A job with the correct coordinate system already configured

Trimble Access version

The menu paths in this guide apply to Trimble Access 2022 and later. Earlier versions use the same settings but may have slightly different navigation. If your menus look different, check the Trimble Access help documentation for your specific version.

Step 1 — Create or edit a rover survey style

Open Survey Styles
From the main menu, go to Settings → Survey Styles. Tap an existing rover style to edit it, or tap New to create one. Name it something descriptive like “NTRIP Rover”.
Set the survey type to RTK
In the survey style, set Survey type to RTK. Under Rover options, ensure your receiver model is selected correctly.

Step 2 — Configure the internet data link

Open Rover radio / data link settings
Inside the survey style, tap Rover radio (or Data link depending on your version). Set the Type to Internet connection.
Set Internet source to Controller internet — this uses the controller's own SIM or Wi-Fi connection. If the receiver has a built-in SIM, you can alternatively select Receiver internet.

Step 3 — Enter NTRIP settings

Enable NTRIP and enter server details
Set the Use NTRIP switch to Yes. Fill in the connection details from your NTRIP service. For RTKsub:
IP Addressntrip.rtksub.com
IP Port2101
NTRIP usernameyour username
NTRIP passwordyour password
Mountpointleave blank to choose on start or enter one directly
Leave Mountpoint name empty for now — Trimble Access will present a list of available mountpoints when you start the survey. You can also enter one directly here to skip selection on each job start.
Configure NTRIP version and GGA
Leave Use NTRIP v1.0 unchecked. Trimble Access automatically negotiates NTRIP version 2.0 if the server supports it — which all modern services do. Only check this box if you encounter connection problems.
For VRS mountpoints, check Send user identity info (or ensure GGA transmission is enabled). This sends your rover's position to the server so it can generate a virtual reference station near you.
Tap Accept to save the survey style.

Step 4 — Start the survey and select mountpoint

Open a job and start survey
Open or create a job with the correct coordinate system. From the main menu tap Survey and select the NTRIP rover style you just created.
Trimble Access connects to the receiver via Bluetooth, then establishes an internet connection to the NTRIP server.
Select a mountpoint from the source table
A list of available mountpoints appears automatically. The list can be sorted by Distance, Format or Mountpoint name. Tap a row to see more detail about that stream.
For Trimble receivers, select the MSM7 mountpoint — RTCM3_NL_MSM7 — for maximum precision. For baselines over 30 km, choose the VRS mountpoint RTCM3_NL_VRS.
Tap Accept. Corrections begin streaming immediately.
Verify RTK Fixed
Watch the position quality indicator in the status bar. It progresses from Autonomous → DGPS → Float → Fixed. In good conditions with a nearby reference station, Fixed arrives within 10–60 seconds.
Once Fixed, your position is centimetre-accurate and you are ready to measure or stake out.

RTK Fixed confirmed

Trimble Access shows “Fixed” in the position quality bar. The solution indicator turns green. You can verify correction flow in Instrument → Receiver Status → Data Link — the bytes received counter should be incrementing steadily.

Using VRS with Trimble Access

Trimble receivers work excellently with VRS (Virtual Reference Station) mountpoints. VRS eliminates baseline distance as a factor by generating a synthetic reference station close to your rover's position.

To use VRS in Trimble Access, the software must send your rover's NMEA GGA position to the NTRIP server. Trimble Access does this automatically when GGA transmission is enabled — which it is by default when NTRIP is active.

VRS and coordinate systems in Trimble Access

When you select a VRS mountpoint, Trimble Access may display a warning that the base data coordinate system differs from the job coordinate system. This is normal — the VRS stream is always in ETRS89/WGS84. Your job coordinate system, for example RD New for the Netherlands, is applied separately through the calibration or datum transformation in the job settings. Dismiss the warning and continue — positions collected will be in your job's coordinate system.

Troubleshooting

Problem	Likely cause	Fix
Cannot connect to NTRIP server	No internet, port 2101 blocked or wrong host	Test internet by opening a browser. Switch from Wi-Fi to mobile data. Check host address — no `http://` prefix.
Sourcetable loads but no mountpoints match	Wrong credentials or server returns empty table	Verify username and password. Check subscription is active. Try logging in via a browser at the server address.
Stuck on Float — not reaching Fixed	Long baseline, obstructions, wrong mountpoint	Switch to VRS mountpoint. Check distance to nearest reference station. Move to open sky.
Warning: coordinate system mismatch	VRS stream in WGS84, job in local datum	This is normal. Dismiss the warning. Verify your job has the correct coordinate system and datum transformation configured.
Connection drops after a few minutes	Unstable mobile data in working area	Check signal strength. Use a dedicated mobile hotspot. Trimble Access automatically reconnects — wait for it to re-establish.
Fixed position has large offset from known points	Wrong coordinate system or datum transformation	Check job coordinate system. For Netherlands, verify RDNAPTRANS transformation is applied. For UK, verify OSTN15 is active.
Force NTRIP v1.0 message	Server or network does not support NTRIP v2	In the survey style data link settings, check Use NTRIP v1.0. This forces the older protocol compatible with all servers.

Receiver-specific notes

Trimble R12 and R12i: The R12i has a built-in IMU for tilt compensation. When using NTRIP with the R12i, ensure the receiver has achieved a Fixed solution before activating tilt compensation — the IMU requires RTK Fix to calibrate correctly.

The R12 supports all RTCM3 MSM levels. Use MSM7 for best results. The R12i's RealFill technology may require a brief additional initialisation period at longer baselines — this is normal.

Internet source: the R12 and R12i do not have a built-in SIM. Use Controller internet or tether the controller to a phone hotspot.

Use the same NTRIP survey style. Confirm that the controller has a stable internet connection and select MSM7 for the highest available observation precision.

Configure the receiver and controller with the same internet data-link settings. Select VRS for longer baselines and confirm the data-link byte counter is increasing.

The R780 supports modern MSM mountpoints. Use MSM7 for survey work and VRS when your nearest physical reference station is more than 30 km away.