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Satellite-Based Augmentation Systems (SBAS) have long played a crucial role in improving GNSS accuracy and integrity for safety-critical applications. From aviation to maritime navigation, SBAS ensures sub-meter positioning and real-time integrity monitoring. But as new augmentation systems emerge and dual-frequency multi-constellation (DFMC) capabilities gain traction, testing requirements are evolving. Understanding these changes is essential for ensuring compatibility, reliability, and compliance in an increasingly complex GNSS landscape.
What is SBAS, Who Uses It, and Why?
SBAS is a GNSS enhancement technology that corrects positioning errors caused by atmospheric interference, satellite orbit inaccuracies, and clock drift. It achieves this by using a network of ground monitoring stations and geostationary satellites to provide real-time correction data to user receivers. The result is improved accuracy, typically bringing positioning down to sub-meter levels.
SBAS is widely adopted in sectors where precision is critical, including:
Aviation: Enabling safer precision approaches and landings.
Maritime Navigation: Improving accuracy for port approaches and offshore operations.
Precision Agriculture: Supporting automated guidance and yield optimization.
The key advantages of SBAS include:
Enhanced Accuracy: Significant improvement over standard GNSS positioning.
Integrity Monitoring: Real-time alerts when positioning errors exceed safety thresholds.
Wide Area Coverage: Some SBAS cover an entire continent, while a combination of SBAS can deliver coverage over most of the world’s landmass.
The Evolution of SBAS – New Systems and DFMC Capabilities
Several key trends are shaping the future of SBAS. The first is the advent of new systems. While legacy SBAS such as WAAS (North America), EGNOS (Europe), and MSAS (Japan) have provided reliable augmentation for years, newer systems like SouthPAN (Australia/New Zealand), KASS (Korea), and ANGA (Africa) are expanding global coverage.
Second is the adoption of Dual-Frequency Multi-Constellation (DFMC) user technology. Traditional SBAS solutions primarily augment GPS L1 signals. DFMC SBAS, however, extends support to multiple frequencies (such as L1/L5) and multiple constellations (including Galileo, BeiDou, and others). This reduces reliance on ionospheric models, enhances resilience, and improves accuracy in diverse environments.
As these developments progress, ensuring compatibility and performance across all SBAS systems—both existing and emerging—is essential for industries that depend on precise positioning. Testing solutions that can simulate and validate SBAS performance across various signals and configurations will be critical to maintaining reliability in real-world conditions.
Testing SBAS with Spirent
Gaining the greatest possible benefit from SBAS means being able to use it around the globe – particularly in global industries like civil aviation. This means being able to test the various systems in concert. As of PosApp release 10.02, Spirent will support testing with:
WAAS
EGNOS
GAGAN
BDSBAS
MSAS
South Pan
KASS
ANGA
UKSBAS
SDCM
All SBAS constellations on Spirent simulators are able to transmit L1 signals, with data compliant to RTCA DO-229. All constellations except BeiDou and SDCM can also transmit L5 signals, with data compliant to EUROCAE ED-259. Combined with the most comprehensive and highest fidelity GNSS signal generation, Spirent simulation systems offer a complete solution for testing performance and compatibility for all use cases
For 40 years, Spirent has been committed to ensuring our users are able to test with the latest ICDs at the earliest possible opportunity. To find out more about Spirent simulation systems, visit our website.
