Utility Scout supports external RTK GPS receivers for survey-grade positioning. When connected, pole locations and GPS updates use centimeter-level accuracy instead of the standard iPhone GPS (which is accurate within a few meters). This guide covers setup, configuration, and troubleshooting.
In This Guide
What Is RTK GPS?
RTK (Real-Time Kinematic) GPS uses correction data from a base station or network to achieve centimeter-level positioning accuracy, compared to the few-meter accuracy of a standard iPhone GPS. This is especially valuable for projects that require precise pole locations for engineering and design work.
Supported Hardware
Utility Scout currently supports the Emlid Reach RX receiver. It connects to your iPhone via Bluetooth.
Note: Other RTK receivers (Trimble, Bad Elf, Arrow, etc.) are not currently supported. Only the Emlid Reach RX is integrated with Utility Scout.
Initial Setup
If this is your first time setting up Utility Scout on a new device, complete the Utility Scout Field App Onboarding steps before configuring RTK GPS.
Pair the Reach RX with your iPhone via Bluetooth in your iPhone's Settings
Download the Emlid Flow app from the App Store (this is used for NTRIP configuration)
Open Utility Scout. The receiver is detected automatically when connected via Bluetooth.
You'll see an RTK status indicator appear on the map showing the current fix quality and accuracy
Tip: Once paired, the Reach RX will reconnect automatically whenever it's powered on and within Bluetooth range. You only need to pair it once.
You can also view detailed connection status, accuracy information, and satellite data in the app's External GPS settings. If the receiver doesn't connect automatically, tap Refresh Connection in the External GPS settings to manually re-establish the connection.
Configuring NTRIP Corrections
RTK accuracy requires a correction data stream, which is configured through the Emlid Flow app (not Utility Scout). NTRIP is a protocol that delivers these corrections over the internet from a base station network.
To configure:
Open the Emlid Flow app (or tap the "Open Emlid Flow for RTK" prompt in Utility Scout)
Set up your NTRIP connection with the correction service provider your organization uses
Once configured, corrections stream automatically to the Reach RX over Bluetooth
Return to Utility Scout. The status indicator will update to show RTK accuracy once corrections are flowing.
Important: Without NTRIP corrections, the Reach RX provides standard GPS accuracy (similar to iPhone GPS). The "RTK Fixed" status that gives centimeter accuracy requires an active correction stream.
Understanding the RTK Status Indicator
When the Reach RX is connected, an indicator appears on the map showing the current GPS fix quality. The indicator color tells you the accuracy level:
Color | Fix Quality | Accuracy |
Green (pulsing) | RTK Fixed | Centimeter-level. This is the target accuracy for survey-grade work. |
Orange (pulsing) | RTK Float | Decimeter-level. The receiver is processing corrections but hasn't locked to a full fix yet. |
Cyan | DGPS | Differential GPS. Better than standard but not RTK-level. |
Blue | Standard GPS | Meter-level accuracy. Similar to iPhone GPS. |
Red | No Fix | The receiver can't determine a position. Usually caused by obstructed sky view. |
Horizontal and vertical accuracy values are displayed directly on the status indicator (H: and V: labels). If the receiver is connected but not receiving corrections, tapping the indicator will open the Emlid Flow app where you can configure your correction source.
How Utility Scout Uses RTK Data
Utility Scout automatically selects the best available GPS source using this priority:
Emlid RTK (if connected and receiving corrections)
Emlid Standard GPS (if connected but no corrections)
iPhone GPS (fallback if receiver is disconnected or data is stale)
You don't need to manually switch between sources. If the receiver disconnects or its data becomes stale (more than 5 seconds old), the app automatically falls back to iPhone GPS. When the receiver reconnects, it switches back.
GPS metadata (accuracy, fix quality, satellite count, correction age) is saved with every location update, so you have a record of the accuracy used for each pole. RTK positioning works alongside all measurement workflows described in the Utility Scout Measurement Workflows guide.
Note: When you tap Update Location on a pole, the app uses whichever GPS source is currently active. Check the status indicator to confirm you're on RTK before updating critical locations.
Troubleshooting
"Open Emlid Flow for RTK" prompt appears
This means the Reach RX is connected but not receiving correction data. Open Emlid Flow and verify your NTRIP connection is configured and active.
Status stuck on blue or cyan
The receiver is connected but corrections aren't flowing. Common causes:
NTRIP is not configured in Emlid Flow
Your correction service is offline or your subscription has expired
No internet connection for the NTRIP stream (corrections require cellular or WiFi)
Status shows red (No Fix)
The receiver can't lock onto enough satellites. This happens under heavy tree canopy, near tall buildings, or indoors. Move to an area with a clearer view of the sky.
Receiver not detected in Utility Scout
Check that the Reach RX is powered on and has battery
Verify Bluetooth is enabled on your iPhone
Check that the device is paired in iPhone Settings > Bluetooth
Restart the Reach RX, then restart Utility Scout
Accuracy values seem wrong
If the status shows RTK Fixed (green) but the accuracy numbers seem high, the correction stream may be coming from a distant base station. Check with your NTRIP provider to confirm you're connected to the nearest available station.
GPS data stops unexpectedly
If GPS data stops flowing for more than 10 seconds (for example, due to brief signal loss), the receiver will disconnect automatically. The app will fall back to iPhone GPS until the connection is re-established.
Tips & Reminders
Charge the Reach RX before each field day. Low battery can cause disconnects.
RTK accuracy depends on your correction service provider. Check coverage for your work area.
The receiver works best in open sky. Tree canopy, buildings, and terrain all degrade accuracy.
You only need to pair the receiver once. It reconnects automatically when powered on.
NTRIP corrections require an internet connection (cellular or WiFi). The GPS receiver itself works offline, but at standard (non-RTK) accuracy.
Check the status indicator before updating pole locations to confirm you're getting RTK accuracy.
Accuracy is displayed in centimeters when under 1 meter, otherwise in meters (or inches/feet in imperial mode).
GPS metadata is saved with every location update, providing an accuracy audit trail for each pole.
Related Articles
Utility Scout Measurement Workflows - Complete guide to pole, midspan, and guy wire measurement
Utility Scout Field App Onboarding - Initial setup and getting started