SW Maps RTK Setup with Kalmix SCOUT over USB-C
Kalmix SCOUT PRO / SCOUT plugs into an Android phone with its integrated USB-C cable. The phone powers the receiver and reads its GNSS output over the same connection.
SW Maps reads the receiver as a USB Serial device and has a built-in NTRIP client, so no additional app is needed to reach an RTK solution. This guide covers the full setup, from installing the app to confirming an RTK Fix on the map.
Verified setup
SW Maps
What SW Maps does
SW Maps is a free Android and iOS field mapping app from Aviyaan Tech. It is built for survey and GIS data collection: recording points, lines and areas with attributes, logging tracks, staking out saved coordinates, and exporting the result to common GIS formats.
Two of its features remove the need for any helper app. SW Maps can read positions from an external GNSS device over USB serial or Bluetooth instead of the phone's internal chip, and it has an NTRIP client built in, so it pulls the correction stream and passes it to the receiver itself.
The Android build is on Google Play, and the developer publishes a full user manual on the SW Maps site. This guide covers only the parts that concern connecting a Kalmix receiver and getting corrections into it. Everything here was verified on the Android build over USB Serial; the iOS build was not tested.
Before you start
What you need
- A Kalmix SCOUT PRO / SCOUT receiver. The integrated 3 m USB-C cable is the only connection required, so there is no adapter or separate cable to prepare.
- An Android phone or tablet with a USB-C port and USB OTG support.
- The SW Maps app, installed from Google Play.
- An NTRIP account: caster address, port, mount point, username, and password.
- An outdoor spot with a clear view of the sky.
Set up SW Maps
Install SW Maps
Install SW Maps from Google Play on the Android device you will use in the field. No driver, plugin, or companion app is needed.
Connect the receiver over USB-C
Plug the receiver's USB-C connector into the phone. Android detects it as a USB device and asks whether to open SW Maps. Tap OK. Tick the option to always open SW Maps for this device if you want it to launch automatically next time.
Place the receiver where it has a clear view of the sky before checking the position.
USB port and battery
Only one app can hold the USB serial port, so close any other GNSS app before connecting in SW Maps. The receiver also draws its power from the phone, and how fast that drains the battery differs from phone to phone, so check the level before a long session.
Create or open a project
Open SW Maps and create a new project, or select an existing one. Both the GNSS connection and the NTRIP settings live inside the project workspace.
Set up the external GNSS connection
Tap the SW Maps icon in the top-left corner of the map view to open the side menu. Everything in this guide lives in that menu, under Instruments. Select External GNSS Connection, then set:
- Connection Mode — USB Serial
- Device — USB Serial
- Instrument Model — Generic NMEA
- Baud Rate — 115200. SCOUT PRO / SCOUT both output standard NMEA 0183 at 115,200 bps by default.
- Instrument Height — your pole or antenna height. Leave it at 0.000 m if you are only testing.
Tap Connect. SW Maps starts showing live data from the receiver: latitude, longitude, elevation, data rate, and solution status.
Set up the NTRIP client
Open the side menu again and select NTRIP Client, one entry below GNSS Status and Skyplot. If no profile exists yet, tap + to create one, then fill in the details from your correction service:
- Name — any label you like.
- NTRIP Version — use the version your caster requires. This test used NTRIP version 1, which is also the default in SW Maps.
- NTRIP Address and Port — your caster server and port.
- Mount Point — the mount point from your service.
- Username and Password — your account credentials.
- Send NMEA GGA to Base Station — enable this for VRS or nearest-base services, which read your rover position from the GGA sentence to generate corrections. Leave it off for a fixed single-base mount point.
Tap Save, select the profile, then tap Connect. SW Maps sends the correction data back to the receiver over the same USB-C connection, so the RTK solution is calculated inside the receiver.
Check the position on the map
Close the menu and return to the map. The strip below the title bar is the status bar. It reports every link in the chain at once: from left to right it shows a USB icon, an NTRIP cloud icon, a satellite icon with the solution status and satellite count, and the age of corrections with horizontal and vertical accuracy.
The USB icon and the NTRIP cloud icon turn green once each link is up. The satellite icon and the position marker on the map both change color with the solution status, so you can read the fix state from the map without opening any other screen. Age of corrections held at 1.0 s throughout this test.
For more detail, open Skyplot or GNSS Status from the side menu to see satellite distribution, signal levels, coordinates, and accuracy estimates.
Read the SW Maps status bar
The setup is working when the USB and NTRIP icons are both green, the status bar reads RTK FIX, and the age of corrections keeps updating instead of freezing.
SW Maps shows the solution status in two places at once, and both use the same color, so you can read the fix state from the map alone. The four states are:
| Status | Color | What it means |
|---|---|---|
| SINGLE | Red | Standalone GNSS positioning. No correction data is being used. This test reported 6.9 m horizontal and 7.3 m vertical accuracy. |
| DGPS | Blue | A differential correction is in use, but the receiver has not produced a carrier-phase solution. |
| FLOAT | Orange | A carrier-phase solution with unresolved ambiguities. Accuracy sits between DGPS and RTK FIX. |
| RTK FIX | Green | A fixed carrier-phase solution. This is the target state for high-accuracy work. |
These are states, not a fixed sequence. A receiver with a good correction stream and a clear sky view can move to RTK FIX without spending time in the others.
SW Maps troubleshooting
These four cases cover the connection failures we hit while testing. The status bar identifies which one you are in before you open any other screen:
| Problem | What to check |
|---|---|
| No USB Serial device appears | Unplug and reconnect the receiver, and confirm you accepted the Android prompt. Check that the phone supports USB OTG, and that no other app is already holding the port. |
| Connected, but no position data | Check that Baud Rate is 115200 and Instrument Model is Generic NMEA. Move the receiver somewhere with a clearer view of the sky. |
| NTRIP connects but never reaches RTK FIX | Check the mount point and credentials, and confirm the phone has a stable internet connection. VRS and nearest-base services need Send NMEA GGA to Base Station enabled. |
| Status stays on SINGLE | Check whether the NTRIP cloud icon is green. If it is not, the correction stream is not reaching the receiver and the solution stays standalone. |
Frequently Asked Questions
Does SCOUT PRO / SCOUT work with SW Maps without any additional app?
Yes. SW Maps reads the receiver directly as a USB Serial device and includes its own NTRIP client, so no bridge or driver app is required. The phone supplies power and carries data over the same USB-C connection.
Which baud rate and instrument model should I use?
Set Baud Rate to 115200 and Instrument Model to Generic NMEA. SCOUT PRO / SCOUT output standard NMEA 0183 at 115,200 bps by default, so no vendor-specific profile is needed in SW Maps.
When should I enable Send NMEA GGA to Base Station?
Enable it when your correction service needs to know where the rover is. VRS and nearest-base services read your position from the GGA sentence to generate or select corrections. For a fixed single-base mount point that does not require a rover position, leave it disabled.
Why does the status show DGPS instead of RTK FIX?
DGPS means a correction is being applied but the receiver has not resolved a carrier-phase solution. Common causes are an obstructed sky view, a correction stream that has stalled, or a base station too far away. Move to a more open location and check that the age of corrections is still updating.
Receivers used in this test
Both receivers ran the setup above. They share the same enclosure, host interface, and default NMEA output.
Kalmix SCOUT PRO
L1/L5 RTK receiver for field and machine deployment. Verified here over USB Serial at 115,200 bps.
View SCOUT PRO →
Kalmix SCOUT
Entry-level L1/L5 RTK receiver for evaluation and prototyping. Same USB-C host interface and NMEA output.
View SCOUT →Using a different Android app? Contact Kalmix support →