SW Maps

SW Maps is a free Android GIS and mapping application that doubles as one of the best NTRIP clients available on mobile. It connects to external Bluetooth GNSS receivers such as the SparkFun RTK Facet, ArduSimple simpleRTK2B, and any u-blox ZED-F9P-based board. SW Maps streams RTK corrections from an NTRIP caster like RTKdata.com directly to your receiver, delivering centimeter-level accuracy for survey-grade field data collection.

Download: Google Play Store (free)

Requirements

• Android phone or tablet with internet access (mobile data or Wi-Fi hotspot)

• Bluetooth-capable GNSS receiver (SparkFun RTK Facet, ArduSimple, u-blox F9P board, etc.)

• GNSS antenna with clear sky view (survey pole or tripod recommended)

• Active RTKdata.com account with username and password

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Step-by-step setup

1

Connect your Bluetooth GNSS receiver

1. Power on your GNSS receiver and enable Bluetooth on your Android phone.

2. Open SW Maps and tap the Bluetooth icon in the top toolbar (or go to Menu → Bluetooth GNSS).

3. Tap Scan to discover nearby devices. Select your receiver from the list.

4. Set the Instrument Model to match your hardware (e.g., "Generic RTK Receiver" or your specific model).

5. Set the Instrument Height to your pole or tripod height.

6. Tap Connect. The status bar should begin showing coordinates from the external receiver.

Phone GPS vs. External Receiver: After connecting, verify that coordinates come from your external receiver, not the phone's internal GPS. Phone GPS accuracy is typically 5–15 m. Your external receiver should show 1–3 m accuracy before corrections. If the accuracy indicator shows 10+ m, the app is still using the phone's internal GPS. Reconnect via Bluetooth GNSS and confirm the source has switched.

2

Open the NTRIP client

1. Tap the Menu icon (three horizontal lines) in the top-left corner.

2. Tap NTRIP Client.

3. Tap Add New Profile (or the + button).

4. Enter a profile name (e.g., "RTKdata EU" or "RTKdata NA").

3

Enter RTKdata.com connection settings

Fill in the following fields:

• Send NMEA GGA to Caster: Enabled (ON)

North America

• Host (domain): 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 (recommended) — or AUTO_WGS84, AUTO_ITRF2020, AUTO_ITRF2014

Europe

Australia

The Send NMEA GGA to Caster toggle must be ON. RTKdata.com uses your GGA position to generate corrections from the nearest Virtual Reference Station. Without GGA, the caster cannot compute corrections and you will remain stuck on FLOAT indefinitely.

4

Connect and verify RTK FIX

1. Tap Connect to start the NTRIP correction stream.

2. Watch the status bar at the top as the solution progresses: Autonomous → DGPS → Float → FIX.

3. Once you see RTK FIX, you have centimeter-level accuracy. This typically takes 10–60 seconds under clear sky.

How to verify RTK is working:

• Solution type in the status bar reads FIX (not Float or Autonomous).

• Horizontal accuracy drops to 0.01–0.02 m (1–2 cm).

• Age of corrections stays below 5 seconds (visible in the NMEA data stream).

• The NTRIP icon in the toolbar shows an active connection (no red X).

Troubleshooting

Problem	Cause	Fix
Position shows phone GPS (10+ m accuracy)	External receiver not connected	Go to Bluetooth GNSS, reconnect receiver, verify coordinates change
NTRIP connects but stays on FLOAT	GGA not sent to server	Enable Send NMEA GGA to Caster in the NTRIP profile
"Connection refused" or timeout	Wrong host/port or no internet	Double-check hostname spelling and port 2101
Mountpoint error or "No data"	Mountpoint not uppercase	Enter AUTO in ALL CAPS, not auto or Auto
Corrections received but accuracy poor	Obstructed sky view	Move to open sky; avoid trees, buildings, overhead cover
Receiver pairs but no position data	Wrong protocol	Ensure NMEA output is enabled on the receiver over Bluetooth

Tips for best results

• Always confirm your position source. SW Maps defaults to phone GPS if no Bluetooth device is connected. Double-check before collecting data.

• Save your NTRIP profile. The profile persists between sessions so you only configure credentials once.

• Export data in GeoJSON, KML, CSV, or Shapefile format directly from the app.

• Check satellite count. Tap the satellite icon to see tracking status. You need at least 10–12 satellites for reliable FIX.

• If FIX drops repeatedly, check receiver firmware and ensure the antenna has a proper ground plane.