Sokkia GCX3 / GRX3 RTK Setup: MAGNET Field

Set up the Sokkia GCX3 and GRX3 with RTKdata NTRIP in MAGNET Field. Receiver or controller internet, mountpoint AUTO typed manually, GGA, and tilt setup.

The Sokkia GCX3 and GRX3 are professional survey-grade GNSS receivers by Sokkia (a Topcon subsidiary). The GCX3 is the flagship model featuring a built-in 4G modem, IMU tilt compensation, and multi-constellation tracking. The GRX3 is a versatile receiver — some models include an internal modem while others rely on a controller for internet connectivity (check your specific model variant). Both receivers are configured through MAGNET Field (Sokkia edition) running on an SHC5000 or SHC500 controller.

Requirements

• Sokkia GCX3 or GRX3 powered on with clear sky visibility

• MAGNET Field (Sokkia edition) v7.0+ on an SHC5000, SHC500, or compatible controller

• Internet connection via the receiver's internal 4G modem (SIM card) or the controller's cellular/Wi-Fi connection

• RTKdata.com account with active RTK credentials (username starting with rtk and password from your RTK dashboard)

• Survey pole with Sokkia adapter

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Step-by-step setup

Sokkia is a Topcon subsidiary — MAGNET Field (Sokkia edition) follows the same workflow as the Topcon version. If you are familiar with Topcon HiPer receivers, the NTRIP configuration is identical.

1

Connect to the receiver

1. Power on your GCX3 or GRX3 and wait for satellite tracking to begin (LED indicators confirm satellite lock).

2. Open MAGNET Field on your SHC5000 or SHC500 controller.

3. Go to Configure > Survey Styles and create a new style or edit an existing one.

4. Under Instrument, select your Sokkia receiver from the Bluetooth device list and pair if prompted.

2

Configure the RTK rover correction source

1. In your survey style, navigate to RTK > Rover.

2. Set Correction Source to Internet (NTRIP).

3. If using the GCX3's internal modem (or GRX3 with modem): select Receiver Internet and configure the APN for your mobile carrier if not already set.

4. If using the controller's internet: select Controller Internet and ensure the controller has an active data connection via cellular or Wi-Fi hotspot.

Not all GRX3 models include an internal modem. If your GRX3 does not have a built-in modem, you must use the controller's internet connection.

3

Enter RTKdata.com NTRIP settings

Fill in the NTRIP connection fields. Select the tab for your region:

North America

• Host / Caster Address: rtk.rtkdata.com

• Host (IP fallback): 13.56.117.10

• Port: 2101

• Username / Password: From RTK Credentials in the internal dashboard (not website login)

• Mountpoint (ALL CAPS): AUTO

Europe

Australia

Type AUTO manually in all capital letters. Do not browse the mountpoint table — MAGNET Field may time out or return an incomplete list with large casters.

4

Verify GGA position sending

1. In the NTRIP settings, verify that Send GGA is set to On or Automatic.

2. MAGNET Field typically enables GGA by default, but confirm this has not been changed.

RTKdata requires GGA position data to select the nearest base station. Without GGA, the connection will succeed but no corrections will be delivered.

5

Start the RTK survey

1. Save the survey style and return to the main screen.

2. Tap Survey and select the style you just configured.

3. MAGNET Field will connect to the internet, then to the RTKdata NTRIP caster.

4. Watch the solution status: Autonomous > Float > Fixed.

5. Once Fixed, you are ready to collect points, stake out, or run your survey workflow.

GCX3 tilt compensation

The GCX3 features IMU-based tilt compensation. Once an RTK Fix is achieved, tilt compensation initializes after a brief walk calibration. You can then measure with the pole tilted without leveling. The controller displays a tilt icon and compensated position in real time.

Vertical reference (heights)

Heights from RTKdata.com are ellipsoidal, not orthometric (mean sea level). Configure a geoid model in MAGNET Field under Configure > Coordinate System > Vertical Adjustment if your project requires orthometric heights.

Troubleshooting

Problem	Cause	Fix
No internet connection (receiver modem)	SIM card not active or APN misconfigured	Verify the SIM card has data. Configure the correct APN for your carrier in MAGNET Field or the receiver's network settings.
No internet connection (controller)	Controller has no data connection	Ensure the controller is connected to cellular data or a phone hotspot.
Empty mountpoint list	Source table timeout or wrong host	Do not browse — type AUTO manually in all caps. Verify the host address is correct.
No corrections received	GGA sending disabled	Verify Send GGA is enabled in the NTRIP settings. RTKdata requires GGA to select the nearest base.
Stuck on Float	Poor sky conditions or far from base	Move to open sky. Check RTKdata base coverage at rtkdata.com.
Credentials rejected	Using website login instead of RTK credentials	Use the username (starting with rtk) and password from your RTK dashboard, not your website account.
NTRIP v2.0 features not available	MAGNET Field version too old	Update to MAGNET Field v7.0 or later for full NTRIP v2.0 support.

Tips and tricks

• GCX3's built-in 4G modem provides the most reliable connection — insert a SIM card and select Receiver Internet to avoid phone hotspot dependency.

• The MAGNET Field workflow is identical to Topcon — if your crew uses both Sokkia and Topcon receivers, the same survey styles and NTRIP settings apply.

• Save the survey style so your entire crew can load it on their controllers without re-entering settings each day.

• Update to MAGNET Field v7.0+ for NTRIP v2.0 support, improved connection handling, and the latest constellation support.

• Check correction age on the MAGNET Field status bar. Values above 5 seconds indicate an unstable internet link.

• Keep receiver firmware updated via Sokkia's Receiver Utility to benefit from the latest RTK engine improvements.

Related Industry Solutions

• Surveying

• Construction