The ESA SISNeT Project: Current Status and Future Plans

Likewise other Satellite Based Augmentation Systems (SBAS), EGNOS– the European SBAS – will broadcast augmentation signals for GPS through Geostationary Earth Orbit (GEO) satellites. GEO broadcasting is proved to be an efficient strategy for avionic applications and other modes of transport. For some applications, though, it may be of interest to complement GEO broadcasting through other transmission means. For instance, building obstacles in cities or rural canyons may difficult the GEO reception. In those situations, complementary realtime Internet-based broadcasting of the EGNOS signal is of major interest as a way to continue taking the most of the EGNOS potential, irrespectively of the user environment. Responding to that need, ESA developed and launched the SISNeT service in 2001. SISNeT allows retrieving the EGNOS messages across the Internet in real-time, usually through wireless networks, like GSM or GPRS. Thanks to SISNeT, any user with access to the Internet (e.g. through wireless networks – GSM or GPRS –) may access the EGNOS product, irrespectively of the GEO visibility conditions. In the early days of SISNeT, advanced simulation activities revealed that the combination of EGNOS and the almost unlimited capabilities of the Internet could open the door to a lot of innovative applications for Satellite Navigation. The evolution of SISNeT to the date has demonstrated and justified what simulations were anticipating, mainly thanks to: The launch of a number of ESA contracts with European industry, on SISNeT developments. The interest of worldwide companies, organisations and universities on applying SISNeT to a large variety of applications, research and development projects. The ESA internal work on SISNeT. In fact, new application fields based on SISNeT have been identified, like educational applications, help to impaired people, quick initialisation of SBAS receivers, etc. The possibilities of SISNeT have revealed to be beyond ESA initial expectations. This paper presents the current status of the SISNeT Project, including a review of the already performed ESA contracts around the SISNeT technology (PDA and desktop available receivers, trials in urban buses, helping blind pedestrians find their way around, etc.), presenting the ongoing contracts, and also placing the focus on future plans to make SISNeT an integral part of EGNOS. Some ESA contracts, which have considered the SISNeT technology as a potential added value, are also referenced. In addition, the EGNOS Message Server (EMS), a non-real time complement to the SISNeT concept, will be shortly introduced through this paper. The Authors firmly believe that SISNeT, as a solid synergy between SBAS systems and the Internet, will continue opening new doors to innovative developments, and will become a mature technology, as an integral part of the EGNOS system.