What is RTK?
The ACSL SOTEN RTK Module enables centimeter-level positioning accuracy for mapping and surveying missions by applying GNSS correction data in real time. Unlike traditional GPS positioning, RTK (Real-Time Kinematic) uses correction data from a known reference source to improve positional accuracy during flight. When operating with an active RTK Fix, image metadata is georeferenced in real time as data is captured.
Note: SOTEN currently supports RTK workflows through live NTRIP correction services and does not support PPK (Post-Processed Kinematic) workflows.
How RTK Works on SOTEN
The SOTEN RTK workflow relies on correction data delivered through an NTRIP (Networked Transport of RTCM via Internet Protocol) service.
The correction data path is:
- TAITEN Controller connects to an NTRIP source via Wi-Fi.
- TAITEN receives correction data.
- TAITEN forwards corrections to SOTEN through the radio uplink.
- SOTEN calculates its position using corrected GNSS data in real time.
The aircraft itself does not connect directly to the internet. All correction data is relayed through the TAITEN controller.
Supported NTRIP Sources
SOTEN is compatible with standard NTRIP correction services and local base station workflows.
Network RTK Services
Services such as GEODNET provide correction data through an internet connection.
Best for:
- Areas with reliable internet connectivity
- Rapid deployment
- Users without their own base station
Local Base Stations
Base stations such as the Emlid Reach RS2 can provide correction data through a local WiFi hotspot.
Using a base station is ideal for:
- Remote locations
- Areas without cellular coverage
- Independent field operations
Important Note for Base Station Users
When the TAITEN controller is connected to a base station’s WiFi hotspot, that connection is dedicated to RTK communications. Map tiles cannot be downloaded while connected to the base station hotspot.
Before heading to the field:
- Open TAKEOFF
- Download offline map tiles for your mission area
- Verify maps are available before disconnecting from internet access
Installing the RTK Module
Prerequisites
- ACSL RTK Module
- 2.5 mm hex driver (provided)
- TAKEOFF version 2.4.1 or later
- SOTEN aircraft (Nx) firmware version 1.2.25 or later
Before You Begin
Power the aircraft completely off before installing the RTK module. Installing the module while powered off ensures proper detection during startup.
Step 1: Mount the RTK Module
- Align the RTK module with the four mounting hardpoints on top of the aircraft.
- Ensure the USB-C cable comes toward the right side of the aircraft.
- Install all four screws.
- Tighten evenly using a cross-pattern sequence.
- Do not overtighten.
Step 2: Connect the USB-C Cable
- Insert the USB-C connector into the aircraft port.
- Press firmly until fully seated.
- Verify the silicone boot is flush against the port opening.
The silicone boot helps protect the connection from dust and moisture during field operations.
Step 3: Verify Cable Routing
Before flight:
- Confirm the cable is clear of all propeller arcs.
- Ensure there is no tension on the connector.
- Verify the cable cannot snag during operation.
Configuring RTK in TAKEOFF
Verify Module Detection
- Power on the aircraft.
- Power on the TAITEN controller.
- Open TAKEOFF app on TAITEN.
If the RTK module is detected correctly, a white RTK icon will appear at the top of the Flight View screen.
Access RTK Settings
Navigate to: Settings → Drone → RTK
Example Configuration: Emlid Reach RS2
When using an Emlid Reach RS2 in Local NTRIP mode, enter the following credentials:
The mount point, username, and password are case-sensitive. After entering all information, select Start RTK.
After some time, assuming the aircraft (and the base station, if applicable) have an unobstructed view of the sky, then the RTK Status should change from “RTK Float” to “RTK Fix”.
Understanding RTK Status Indicators
| Icon | RTK Module Positioning Status | Positioning Accuracy (reference) |
|---|---|---|
| Not displayed | Not positioning (RTK module not connected) | SOTEN onboard GNSS positioning accuracy |
 | Not positioning (RTK module connected) | SOTEN onboard GNSS positioning accuracy |
 | Standalone positioning or DGNSS | Vertical: 1.0–3.0 m / Horizontal: 1.0–3.0 m |
 | RTK Float | Vertical: 0.5–1.0 m / Horizontal: 0.5–1.0 m |
 | RTK Fixed | Vertical: 0.01 m / Horizontal: 0.01 m |
Note: Icon images are displayed in the TAKEOFF app. Refer to the app for visual reference.
Troubleshooting
RTK Stuck on Float
Common causes include:
- Buildings, terrain, or trees blocking GNSS signals
- Poor base station placement
Move the aircraft or base station to a location with a clearer view of the sky.
“Network Connection Unavailable” Error
Check the following:
- Wi-Fi is enabled on the controller
- Correct network is connected
- NTRIP server address is entered correctly
- Internet connection is available (for network RTK services)
Authentication or Mount Point Errors
If RTK fails to connect:
- Verify username and password
- Confirm mount point spelling
- Check for case-sensitive characters
- Verify port number
Map Tiles Not Loading
This is expected behavior when using a base station hotspot. Because the controller is connected to the base station’s network, it cannot simultaneously access online map services.
Solution: Download mission maps in TAKEOFF before leaving for the field.
RTK Module Not Detected
If the RTK icon does not appear:
- Power off the aircraft.
- Remove and reseat the USB-C connector.
- Confirm the connector clicks into place.
- Verify the silicone boot is fully seated.
- Restart the aircraft.
If the issue persists:
- Power off the aircraft.
- Inspect the connector for debris.
- Clean with compressed air if necessary.
- Reconnect and restart.
Operational Best Practices
- Verify RTK Fixed status before launch.
- Inspect the USB-C connection during every preflight inspection.
- Download map tiles before operating with a local base station hotspot.
- Maintain visual line of sight throughout flight operations.
- Follow all applicable FAA and local aviation regulations.
NOTE: RTK improves positional accuracy but does not replace pilot responsibility or safe operating procedures.