GNSS Master RTK Setup: NTRIP and Android Mock Location
Verified setup
- App version
- 1.5.0.0
- Android
- Android 15/16
- Receivers
- SCOUT PRO / SCOUT
- Last verified
On this page
App guides
App guides
NTRIP Inside
GNSS Master can use a Kalmix SCOUT PRO / SCOUT over USB Serial, receive NTRIP corrections, and publish the corrected position through Android Mock Location—so a compatible target app does not need its own receiver connection.
This guide covers that provider-app path only: USB Serial, NTRIP Client, GNSS Status, and Mock Location. It does not turn every GNSS Master feature or every Android app into part of the verified setup.
What GNSS Master does as an Android GNSS provider
GNSS Master is an Android GNSS bridge and diagnostic app. It manages the GNSS Receiver Connection and Correction Input, while Android Mock Location can provide the corrected position to compatible third-party apps that read the system location. Receiver Data Output is a separate optional function and is not required for the Mock Location workflow in this guide.
Choose the route that matches where the target app expects to receive position. The table below separates the provider workflow in this guide from an app that manages its own receiver connection.
| What you need to do | Recommended path |
|---|---|
| Use corrected GNSS in another Android app | Let GNSS Master manage USB Serial and NTRIP, then enable Android Mock Location. |
| Use an app with its own USB and NTRIP controls | Connect inside that app. The SW Maps setup guide shows one direct workflow. |
| Check the receiver solution | Use GNSS Status and Skyplot inside GNSS Master. |
GNSS Status and Skyplot show the solution type, coordinates, satellites in view and in use, dilution-of-precision values, correction age, reference station ID, satellite distribution, and signal levels. GNSS Master is available from Google Play; its official documentation covers the app's other connection and output modes. For the underlying receiver-to-Android data path, see the Android architecture and data flow guide.
What this guide does not use
GNSS Master exposes more connection, correction, output, and receiver-configuration modes than this tested SCOUT workflow needs. The table below keeps those options from being mistaken for required setup steps.
| GNSS Master feature | Boundary in this guide |
|---|---|
| Receiver configuration | Rover, Base, and configuration-file tools are documented for u-blox and Septentrio receivers. They are not part of this SCOUT setup. |
| Other receiver links | Bluetooth Classic, BLE, and TCP/IP are available in the app, but this guide verifies USB Serial only. |
| Other correction and output modes | PointPerfect, NTRIP Server, TCP Client, and TCP Server are outside this guide. The tested path uses NTRIP Client to the receiver, then Mock Location to a compatible Android app. |
Before you start
What you need
- A Kalmix SCOUT PRO or SCOUT receiver.
- An Android phone or tablet with USB-C and USB OTG support.
- GNSS Master installed on the Android device.
- An NTRIP account: caster address, port, mount point, username, and password.
- Mobile data or Wi-Fi, plus an outdoor location with a clear view of the sky.
Connect SCOUT to GNSS Master over USB serial
-
01
Install GNSS Master and connect the receiver
Install GNSS Master on the Android device you will use in the field. Plug the SCOUT receiver into the phone with the integrated USB-C cable, then open GNSS Master. When Android asks whether GNSS Master should open for this USB device, tap OK. Enable Use by default for this USB device if you want the same app to open automatically next time.
Open GNSS Master after connecting the receiver. 
Tap OK to give GNSS Master access to the USB device. 
The Status page initially shows the links as Not Connected. -
02
Configure the USB Serial receiver link
On the Status page, tap the gear beside GNSS Receiver Connection. Set Mode to USB Serial and Baud Rate to 115200. Refresh the connected-device list if necessary, select the listed USB Serial device, and tap Connect.
Choose USB Serial as the receiver connection mode. 
Use 115200 for both SCOUT PRO and SCOUT. 
Select the detected USB Serial device, then tap Connect. 
Status changes to Connected when the USB link is open. If your workflow uses antenna or instrument-height compensation, enter the measured height and save it with the check mark. Leave it at 0.0 m for a connection test that does not require compensation.
USB port access
Only one Android app can hold the USB serial port at a time. Close any other GNSS utility before connecting in GNSS Master. The receiver is powered by the phone, so monitor the phone battery during long field sessions.
-
03
Create the NTRIP correction profile
Return to Status and tap the gear beside Correction Input. Set Mode to NTRIP Client, then tap the plus sign beside NTRIP Connections. Enter the NTRIP version, caster address, port, mount point, username, and password supplied by your provider.
Enable Send NMEA GGA to Base Station (For VRS/NEAR Stream) when your correction service requires the rover position to create a virtual reference station or choose a nearby base. This uses the receiver's NMEA GGA position sentence. Save the profile when complete.
Select NTRIP Client and tap + to add a profile. 
Enter the connection details from your NTRIP provider. 
Enable GGA when required by the correction service, then save the profile. -
04
Connect the NTRIP stream
Select the saved profile and tap Connect. The Corrections page should change from Not Connected to Connected. Return to Status and confirm that both GNSS Receiver Connection and Correction Input are connected and that their data counters begin increasing.
Select the saved profile, then tap Connect. 
Connected confirms that the NTRIP session is open. -
05
Make the corrected position available to third-party apps
Enable Android Developer options, select GNSS Master as the mock location app, then turn on Mock Location in GNSS Master. Compatible third-party apps that read the Android system location can now use the corrected SCOUT PRO / SCOUT position instead of the phone's internal GNSS.
Open the third-party app and confirm that its position updates from the external receiver before starting fieldwork. GNSS Master also provides a dedicated Output to SW Maps switch for that app's direct input path; the general Mock Location workflow in this guide does not require it.
System location side effect
Mock Location changes the Android system-location route, not only the target app. Turn it off after fieldwork so another app does not continue using the receiver position unexpectedly.
Mock Location serves compatible Android apps; Output to SW Maps is a separate direct path. -
06
Verify the solution in GNSS Status and Skyplot
Open the side menu. Under Status, choose GNSS Status for detailed solution information or Skyplot for satellite geometry and signal levels.
Open GNSS Status or Skyplot from the side menu. In GNSS Status, watch the Fix type field while the receiver tracks satellites and consumes corrections. GNSS Master may report Invalid, Single, DGPS, RTK Float, or RTK Fix.
Invalid: no usable GNSS position yet. 
Single: standalone GNSS positioning. 
RTK Float: carrier-phase ambiguities are not fixed yet. 
RTK Fix: 23 satellites in view, 22 used, PDOP 1.72, and correction age 1.0 s. Open Skyplot to check satellite distribution and signal levels. Look for satellites spread across the sky rather than clustered in one direction.
Skyplot shows position summary, satellite geometry, and signal levels.
Read the GNSS Master fix status
After both the receiver and correction links are connected, use the Fix type field to read the current solution. The table below defines the labels GNSS Master shows; they describe the current solution, not a guaranteed measurement result.
| Fix type | What it means |
|---|---|
| Invalid | No usable GNSS position has been produced yet. |
| Single | Standalone GNSS positioning. RTK corrections are not yet producing a carrier-phase solution. |
| DGPS | Code-based differential corrections are being applied, but there is no carrier-phase RTK solution yet. |
| RTK Float | A carrier-phase solution is active, but the integer ambiguities remain unresolved. |
| RTK Fix | A fixed carrier-phase solution. This is the target state for high-accuracy work. |
The NMEA GST accuracy sentence can be enabled in the receiver output configuration, but it is not part of the default message set to avoid sending extra serial data when those fields are not needed. GST was disabled for these screenshots, so GNSS Master shows horizontal and vertical accuracy as N/A. Compare accuracy values across apps only when they use the same receiver message set and input path.
GNSS Master USB, NTRIP and Mock Location troubleshooting
Use the table below to isolate the failed link before changing another setting: receiver connection, correction input, system-location output, or Android background behavior.
| Problem | What to check |
|---|---|
| No USB device appears | Reconnect the receiver, accept the Android USB prompt, confirm the phone supports USB OTG, tap refresh, and close any app that may already hold the serial port. |
| USB says Connected but data stays at 0 B/s | Confirm the baud rate is 115200, reconnect the cable, use Reconnect All, and check that the receiver has power and is outputting NMEA data. |
| NTRIP does not connect | Recheck the NTRIP version, caster address, port, mount point, username, and password. Confirm the phone has internet access. |
| NTRIP connects but status stays Single | Confirm the correction stream is active. Enable GGA for VRS/NEAR services, move to an open-sky location, and check that the mount point is suitable for the receiver and region. |
| Target app still uses the phone location | In Android Developer options, select GNSS Master as the mock location app. Turn on Mock Location in GNSS Master, then reopen the target app. If SW Maps is already connected directly to another receiver, use its direct USB and NTRIP path instead. |
| Corrections stop in the background or with the screen off | Return to GNSS Master and use Reconnect All if needed. Android battery restrictions can interrupt background networking; exclude GNSS Master from battery optimization where the device allows it, then test the workflow before field use. |
Frequently Asked Questions
How do other Android apps use the corrected GNSS position from GNSS Master?
Select GNSS Master as the mock location app in Android Developer options, then enable Mock Location in GNSS Master. A compatible app that reads the Android system location can then receive the corrected position. For the receiver-to-Android boundary, see Integration with 3rd-Party Apps.
Why does GNSS Master show horizontal and vertical accuracy as N/A?
The GST accuracy sentence was disabled in the receiver output for these screenshots, so GNSS Master showed N/A. Compare accuracy across apps only when the receiver message set and input path are the same.
What is the difference between Output to SW Maps and Mock Location?
Mock Location is the general Android system-location route. Output to SW Maps is a separate app-specific route. Use one receiver path in SW Maps at a time: if SW Maps already manages another receiver over USB or Bluetooth, use its direct USB and NTRIP workflow instead.
Does GNSS Master keep relaying corrections when the screen is off?
Android battery restrictions can interrupt background networking. Exclude GNSS Master from battery optimization where the device allows it, then confirm that GNSS Receiver Connection and Correction Input remain connected before relying on the workflow in the field.
Receivers used in this test
SCOUT PRO and SCOUT completed the verified GNSS Master USB Serial setup in this guide. Both use the USB-C host interface and default NMEA output recorded here.
Kalmix SCOUT
A compact dual-band RTK G-Mouse for evaluation, prototyping, education, and open-sky deployments.
View SCOUT →Kalmix SCOUT PRO
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