What is RTK?
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Let’s dive a bit deeper into how Real-Time Kinematic (RTK) GPS technology works:
Base Station Setup
To use RTK, you need two important components: the base station and the rover (your GPS device). The base station is set up at a known, fixed location with very precise coordinates. This location is carefully surveyed and its coordinates are accurately measured. The base station is typically placed on a tripod or a permanent secure mount.
Rover (your GPS device)
This is the device you carry or install on a vehicle. It communicates with both the GPS satellites in the sky and the base station on the ground. The rover and the base station have a radio link to exchange data.
GPS Signals from Satellites
Both the base station and the rover receive signals from the same GPS satellites orbiting the Earth. These signals contain information about the satellite’s location and the time the signal was transmitted.
Error Correction
The base station calculates its precise position using the known coordinates. Simultaneously, it also calculates the errors in the GPS signals it receives. These errors can be caused by factors like atmospheric interference or signal delays. The base station then sends correction data to the rover in real-time, typically via radio or cellular signal.
Rover’s Position Calculation
The rover receives the corrected data from the base station. It then uses this data to adjust its own calculations. By comparing the corrected data from the base station with the raw GPS signals it receives from the satellites, the rover can determine its precise position with much higher accuracy.
Centimetre-Level Accuracy
Thanks to the correction data from the base station, RTK can achieve extremely high accuracy, often down to a couple of centimetres or even less. This level of precision is essential for applications where exact positioning is crucial, such as surveying land boundaries, guiding tractors for precision agriculture, ensuring construction projects are on target, or helping autonomous vehicles navigate safely.
Real-Time Updates
The “real-time” part of RTK means that the correction data is continuously updated and sent to the rover as it moves. This ensures that the rover always has the most accurate information, even if it’s on the go.
In Summary
RTK GPS is a technology that uses a base station with a known precise location to correct the GPS signals received by a rover, allowing for highly accurate and real-time positioning. It’s a powerful tool used in various industries where centimetre-level accuracy is essential for tasks like mapping, navigation, and monitoring.