> For the complete documentation index, see [llms.txt](https://docs.premium-positioning.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.premium-positioning.com/guides/hemisphere-s631-s321.md).

# Hemisphere S631 / S321

These steps connect a Hemisphere S631 / S321 to the Premium Positioning correction network over NTRIP, using Carlson SurvCE / SurvPC. They assume you already have your NTRIP credentials.

### Before you start

* Your NTRIP username and password, from your Premium Positioning welcome email or your account on the customer portal.
* Carlson SurvCE / SurvPC.
* A working internet connection on the controller or phone.
* A clear view of the sky at the point you are measuring.

### Network settings

These are the same for every Premium Positioning customer. Only your username and password are unique to you.

* Server or host: rtkpremium.xyz
* Port: 2101
* Mountpoint: COMMON
* Protocol: NTRIP

### Steps

1. Get the receiver internet-ready: You need a live internet path. Easiest: the data collector's own connection (its SIM or a phone/MiFi hotspot). The S631 also has a built-in 4G modem if you fit a SIM and set the APN. Power on and confirm it's tracking satellites.
2. Pair the receiver over Bluetooth: Pair the S631/S321 to the data collector via Bluetooth in the device OS first (it broadcasts under its serial number) so it's available to SurvCE/SurvPC.
3. Open Equip > GPS Rover: Launch Carlson SurvCE/SurvPC, open/start a job, then Equip > GPS Rover. Four tabs appear: Current, Comms, Receiver, RTK.
4. Set Manufacturer and Model (Current tab): Set Manufacturer to 'Hemisphere GNSS' and Model to 'S631' or 'S321'. List wording varies slightly by version - pick the closest Hemisphere entry.
5. Connect on the Comms tab: On Comms set Type to Bluetooth, select the paired S631/S321, and tap the green check / Connect. It reports a successful connection.
6. Choose the internet device (RTK tab): On the RTK tab set Device to 'Data Collector Internet' if the collector/phone provides the connection, or 'Internal GSM' if the SIM is in the receiver (tap the wrenches icon to set the APN).
7. Set Network to NTRIP: Set Network to 'NTRIP', then tap the wrenches icon next to Network to open the NTRIP Broadcasters screen.
8. Add the Premium Positioning caster: Tap New, name it (e.g. 'Premium Positioning'), and enter IP addr (Host) rtkpremium.xyz, Port 2101.
9. Enter YOUR NTRIP credentials: In User and Pwd type the username/password from your Premium Positioning welcome email - unique to you; never use anyone else's.
10. Download the source table: Tap the green check. SurvCE/SurvPC downloads the broadcaster's base list (source table). If nothing returns, recheck internet, host/port, and credentials.
11. Select the COMMON mountpoint: On the Bases screen open the Name dropdown and choose 'COMMON', then tap the green check.
12. Confirm and apply: Tap the green check again to return to the RTK tab. Correction type/format fields are greyed out on purpose - with NTRIP it follows what the caster advertises. Exit GPS Rover with the green check to start streaming.
13. Verify a Fixed solution: Go to Survey > Store Points and watch the status progress Autonomous → Float → FIXED (typically within a minute or two). Wait for FIXED before storing points, then check on a known mark. If you sit on Float, recheck cellular signal, the COMMON mountpoint, and your credentials.

### If the fix will not hold

Names differ slightly between SurvCE and SurvPC versions and firmware; the layout is the same (Equip > GPS Rover, RTK tab, Network = NTRIP, wrenches icon to add the caster). Some crews drive the S631/S321 from Hemisphere's PocketMax app instead - there the path is Config > GNSS Rover > Corrections > NTRIP Client; caster host/port/mountpoint and your credentials are identical. A stable cellular signal is required; if correction age climbs above \~5 s the link is unstable.

For more, see RTK corrections troubleshooting and Fix inconsistent RTK accuracy on site.

### Need help

Support is available 24/7. Include your receiver model, the mountpoint, the solution status, and the correction age when you get in touch.