Bad Elf Flex: Choosing the Right RTK Network for Your Bad Elf GNSS Receiver
Introduction
This guide explains how to achieve centimeter-level accuracy with your Bad Elf Flex and sub-foot accuracy with your Bad Elf Flex Mini Extreme receiver by connecting to a real-time network (RTN) in the USA.
What You’ll Learn
- What are real-time kinematics (RTK)?
- Options for correction sources
- How to use RTK via NTRIP
What is RTK?
Real-time kinematics (RTK) works by streaming data from one or more high-accuracy base stations to provide real-time corrections for the GNSS satellite signals received by your Bad Elf receiver. An RTN is a network of these base stations spread over a wide area, and they generally stream RTK corrections over the internet 24/7. These corrections improve the accuracy of your location data from meters, down to a centimeter.
Accuracy depends good sky view and adherence to best practices. Factors such as multipath (signal reflections near buildings or trees), baseline, nearby structures, radio interference, and weak correction signals can reduce performance.
Vertical error is typically 1.5× horizontal accuracy.
RTN Options
- State-run Networks: Many US states offer free RTN access through their Department of Transportation or other state government department. These networks are a cost-effective option, but availability and coverage can vary. Our Public RTK Network map displays your potential options.
- Subscription Services: Networks like Point One Navigation, Skylark, and GEODNET offer subscription-based RTK services. Typically, private networks will offer interstate coverage and, at minimum, equivalent performance to state networks. You can activate a free 2-week Point One Navigation trial within the Bad Elf Flex App.
The Bad Elf Flex and Flex Mini Extreme require RTCM formatted messages and are not compatible with CMR. In addition, we highly discourage using RTCM 2.x as it will cause severely degraded performance.The Bad Elf Flex Mini Extreme requires MSM corrections, only available through RTNs providing RTCM 3.2 or greater. All three private networks above support this format, however, state networks can vary. Consult our web map for more information.Setting Up Your RTK via NTRIP Connection
- Register a Network Account: Use our Public RTK Network map to find if there’s a suitable state network in your area. A link to the RTN website to register is included in the map pop-up after selecting a state. By zooming in on the map, you can also view base stations and their distance to your location. If no suitable network is available, please consider a paid option above.
- Optional: After selecting a state, click the NTRIP link in the map pop-up to populate your RTK via NTRIP profile in the Bad Elf Flex app. This link needs to be opened on an iOS phone and requires the user to complete their profile with their RTN username and password before connecting. We recommend emailing this link to yourself and tapping it on your phone once you've received your login information from your state RTN of choice.
- Set Up an NTRIP Profile: NTRIP (Networked Transport of RTCM via Internet Protocol) is the standard for streaming RTK corrections. You'll need to create a profile in the Bad Elf Flex app with your RTN login credentials and the specific details of the network you're connecting to.
- See related article: Logging into an NTRIP Network
- Burn a Token (Optional): This unlocks the "Extreme" mode on your Bad Elf Flex Standard, enabling access to RTK.
- The Bad Elf Flex Mini does not use tokens.
*Important Considerations*
- Internet Connection: Connecting to a real-time network (RTN) requires a stable internet connection on your phone or tablet.
- Network Compatibility: Ensure the RTN you choose supports the specific correction format (MSM4+ and RTCM3.2+) required by your Bad Elf Flex Mini Extreme. Note the Bad Elf Flex does not have the same requirements.
- Baseline Distance: Accuracy can be negatively affected by the distance between your receiver and the nearest base station. The maximum distance we would recommend using is ~50 miles or 80 kilometers.
- Mount Point: VRS or iMAX mount points receive your current location and automatically create a virtual reference station to reduce the baseline distance. Near mount points automatically select the nearest base station. Single-baseline solutions require the user to manually choose which base station they want to receive corrections from.
Alternative: Base/Rover RTK Solution
Bad Elf offers a base/rover solution where you set up an additional Bad Elf Flex Extreme unit as the base station and transmit RTK corrections directly to your Bad Elf Flex Extreme rover via an external radio. This eliminates the need for internet connectivity. The solution requires an additional Bad Elf Flex Extreme and two radios.
Frequently Asked Questions
Q: How do I connect a Bad Elf receiver to my phone or tablet?
A:Pair the receiver via Bluetooth. On iOS devices, Bad Elf GNSS receivers use their MFi certification to automatically take over all location services. On Android devices, the same functionality is available by enabling mock location through the Bad Elf Flex App.
iOS pairing instructions: Bad Elf Flex Pairing with Android
Android pairing instructions: Bad Elf Flex: Bluetooth Pairing with Android
Q: Which apps work best with Bad Elf receivers for GIS?
A: Popular choices include ArcGIS Field Maps and Pointman. The Bad Elf Flex App is capable of standalone data collection.
A: Popular choices include ArcGIS Field Maps and Pointman. The Bad Elf Flex App is capable of standalone data collection.
Q: Do I need corrections for sub-meter or centimeter accuracy?
A: With the Bad Elf Flex you do NOT need corrections for sub-meter accuracy, the device gets 30-60cm with just a clear view of the sky.
A: With the Bad Elf Flex you do NOT need corrections for sub-meter accuracy, the device gets 30-60cm with just a clear view of the sky.
Q: What if I work in a remote area with no cellular service for RTK?
A: Use the
Base/Rover Kit
to set up a private radio link between a base and a rover. This allows you to achieve ~1 cm accuracy without relying on a cellular network.
Q: What affects the quality of my GNSS positions in the field?
A: Whenever possible, work in areas with an open sky view. Accuracy can degrade near tall buildings, dense tree canopy, or power lines due to multipath interference. The helical antenna on the Bad Elf Flex helps reduce these effects, and using RTK corrections further improves resilience in challenging environments.
A: Whenever possible, work in areas with an open sky view. Accuracy can degrade near tall buildings, dense tree canopy, or power lines due to multipath interference. The helical antenna on the Bad Elf Flex helps reduce these effects, and using RTK corrections further improves resilience in challenging environments.
Q: How accurate are elevations?
A: Vertical error is typically about 1.5× horizontal accuracy.
For more information about vertical accuracy here are some suggested articles
Q: Can I use the same receiver for both mapping and survey work?
A: Yes. The Bad Elf Flex Mini Extreme can serve as a compact mapping unit with SBAS or as a centimeter-grade receiver when used with RTK.
For heavier survey workflows or when you need better multipath mitigation, use the Bad Elf Flex.
For heavier survey workflows or when you need better multipath mitigation, use the Bad Elf Flex.
Q: Do the devices have screens for field visibility?
A: Yes. Both the Bad Elf Flex Mini and the Bad Elf Flex have on-device screens that display key status information such as satellites, fix type, and corrections.
A: Yes. Both the Bad Elf Flex Mini and the Bad Elf Flex have on-device screens that display key status information such as satellites, fix type, and corrections.
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