Tended devices must be confident in their precise location so they can accurately alert when they enter or exit geofences (safe zones).
In this article, find more out about location reporting and how Tended devices use different technologies for accurate positioning on-site.
What is location accuracy?
When thinking about Tended devices and geofencing projects, accuracy is how close the device thinks it is compared to its real location.
How accurate are the Tended devices?
The devices are highly accurate. Some circumstances may lead to device accuracy dropping beyond an acceptable level, but you'll always be alerted when this happens.
Devices operate above the required confidence level: You can trust your device to notify you accurately if you accidentally stray from safe working limits.
The device logs its location 4 times per second: giving you quick and responsive alerts when you need them.
Why is device accuracy important?
Precision safe zones: On the Tended dashboard, safe zones (geofences) are drawn to cm accuracy around safe working limits; good levels of accuracy allow the device to react quickly to these boundaries.
Real-Time Alerts: With excellent location accuracy and fast updates, devices will alert almost immediately if a track worker exits a safe zone, allowing quick responses.
Accurate Data Logging: When used in asset mode, Tended device locations will be visible from the Dashboard allowing you to monitor the movements and behaviour of site assets accurately.
Key technical terms
GNSS (Global Navigation Satellite System) - space-based satellite systems (GPS is one example) to provide location information anywhere on Earth to devices like smartphones, cars, and planes so they know where they are.
RTK (Real-Time Kinematic) - a method used to make GNSS (or GPS) positioning much more accurate. While regular GNSS can usually give you location accuracy within a few meters, RTK improves that accuracy to just a few centimetres.
Protection levels - safety thresholds used in GNSS systems to indicate how much error might exist in the system’s position estimate. They help ensure that the actual location of a device is within a safe distance from where it appears on the map.
How do Tended devices gain accuracy?
Tended devices use a combination of GNSS technology and RTK correction to achieve high accuracy in their location reporting.
GNSS satellites: The device receives signals from multiple GNSS satellites, which provide basic location information, similar to how your phone's GPS works. This alone is accurate to within a few meters.
RTK correction: To improve accuracy even further, Tended devices use RTK technology. This involves nearby base stations (fixed reference points) with surveyed precise locations. The base stations compare the satellite signals they receive with their known locations and calculate any small offsets. It then sends data to the device in real-time to help it correct its own accuracy.
Protection levels: To ensure that the accuracy provided by the GNSS and RTK systems is dependable, the system uses protection levels. These levels quantify the maximum error that can be expected with a certain probability.
High accuracy: By combining GNSS data, RTK corrections and protection levels, Tended wearables can determine the device's location with centimetre-level accuracy. This level of accuracy is essential for supporting track worker safety and asset positioning in geofencing projects.
About the low accuracy alert
Your device may lose accuracy during your shift due to poor visibility of GNSS. Reasons for this may be:
Obstructed by site equipment or machinery
Antenna covered by worker PPE
Working in a built-up area e.g. high buildings or trees
If your device loses accuracy, you'll receive the following alert:
If you hear this alert, you can continue to carry out your work relying on your primary form of protection and remain aware of your surroundings and safe working limits.
The device will show three solid green lights once accuracy has been regained.
Any questions or issues?
We're here to help! Simply pop us an email at support@tended.co.uk, WhatsApp us on 07713682625 or drop us a message via live chat from the blue bubble in the corner of this page or within the Dashboard 😊