What is VRS (virtual reference station)
Virtual Reference Station (VRS)
Understanding VRS
A Virtual Reference Station (VRS) is a concept used in Global Navigation Satellite System (GNSS) technology to enhance the accuracy and reliability of positioning data. It's a virtual, imaginary reference station created from the data collected by a network of real-time reference stations.
How VRS Works
- Network of Reference Stations: Multiple ground-based reference stations equipped with GNSS receivers collect precise positioning data.
- Data Processing: The collected data is processed at a central processing unit to calculate corrections for various systematic errors like atmospheric delays, satellite orbit errors, and receiver clock errors.
- Virtual Reference Station Creation: Based on the user's position, a virtual reference station is generated. This virtual station is positioned closer to the user than any of the real reference stations.
- Correction Data Generation: Corrections are calculated for this virtual reference station and transmitted to the user's GNSS receiver.
- Differential Correction: The user's receiver applies these corrections to its own measurements, significantly improving positioning accuracy.
Benefits of VRS
- Improved Accuracy: VRS can achieve centimeter-level accuracy, surpassing the limitations of single-reference station RTK.
- Increased Coverage: By combining data from multiple reference stations, VRS can provide coverage in areas where a single reference station might not be sufficient.
- Reliability: VRS is more reliable as it can use data from multiple reference stations, reducing the impact of individual station failures.
- Reduced Baseline: The virtual reference station is typically closer to the user, reducing the baseline distance and improving the accuracy of differential corrections.
VRS vs. Traditional RTK
| Feature | Traditional RTK | VRS |
|---|---|---|
| Reference Station | Single, fixed location | Virtual, calculated from multiple stations |
| Accuracy | Depends on baseline length | Typically higher accuracy due to shorter virtual baseline |
| Coverage | Limited by reference station location | Wider coverage due to network of reference stations |
| Reliability | Vulnerable to single point of failure | More reliable due to redundancy |
VRS and RTK
VRS is often used in conjunction with Real-Time Kinematic (RTK) technology. RTK is a differential GNSS technique that uses carrier phase measurements to achieve centimeter-level accuracy. VRS enhances RTK performance by providing more accurate and reliable reference station data.
Conclusion
VRS is a valuable tool for applications requiring high-precision positioning, such as surveying, construction, and agriculture. By leveraging a network of reference stations, VRS overcomes the limitations of traditional RTK and provides improved accuracy, reliability, and coverage.