Motivation
The current picture of satellite navigation systems includes global (GPS, GLONASS, Galileo), regional (SBAS, QZSS, Compass, IRNSS) and local systems (GBAS, hybrid systems combining GNSS and other sensors). The use of GNSS for safety critical applications requires given levels of confidence on the positioning obtained by the user equipment. This is possible by complementing the core GNSS signals with other systems or techniques to produce a solution with the needed level of integrity.
The analysis of the current trends observed in the navigation community suggests that, for the coming years, the GNSS integrity solutions may rely on SBAS, GBAS, RAIM or new techniques including integration with other sensors. In this global GNSS picture, SBASs appear as feasible solutions to regionally augment the GNSS constellations to provide increased accuracy with integrity.
In the aviation community, SBAS already enjoy recognition at regulatory level and are considered as a reference navigation aid. Recently, ICAO has developed the Performance Based Navigation (PBN) concept and established an international schedule for APV (Approach Procedure with Vertical Guidance) at all instrument runway ends either as the primary approach or as a back-up for precision approaches by 2016 with intermediate milestones of 30% by 2010, and 70% by 2014. Most countries are producing their PBN implementation plans to meet ICAO recommendation and the use of the SBAS technology seems to be one of the most adequate solution.
However, the development and deployment of a SBAS system in any region of the world is a complex challenge. The development of the current operational SBAS systems has required significant time and effort. Besides, each region may have different characteristics and requirements. The ionosphere behavior is, for instance, a key issue for implementation of SBAS in some regions.
As a consequence of the technological challenge, it is usual that SBAS development plans envisage the deployment of SBAS testbeds (e.g.; WAAS NSTB, EGNOS ESTB) and pre-operational, non-certified, services in parallel to the operational system development. Testbeds offer numerous advantages, in particular:
- Testbeds provide the system developers with powerful platforms to validate architecture, design and performance assumptions, thus mitigating design risks and helping to optimize the design to satisfy the requirements of the region.
- Testbeds allow users to benefit from an early SBAS service, representative of the final augmented performance and useful in many applications (e.g.; precision agriculture) which do not require a formal certification process.
- Testbeds help to build a user community and confidence in the system.
- Even for aviation users, which require a certified system, testbeds are very useful tools to better understand and demonstrate to potential users, service providers and regulators the operational benefits of the SBAS solution and learn how to exploit them.
In response to this need, GMV is now offering magicSBAS to any region interested in the quick deployment of a non-safety critical SBAS solution.
