There are three SBAS networks in operation today, the European Geostationary Navigation Overlay Service (EGNOS), the Multifunctional Transport Satellite (MTSAT) Satellite Augmentation System (MSAS) and the United States (US) Wide Area Augmentation System (WAAS), providing coverage geographically to most of Europe, Asia-Pacific and North America. Both India’s GPS Aided Geo Augmented Navigation (GAGAN) and the Russian System of Differential Correction and Monitoring (SDCM) are in development that will provide coverage to Indo-Asia and Euro-Asia. Completion of all five systems will provide near total coverage of the northern hemisphere for approach operations and near worldwide coverage for enroute, terminal and non-precision approach operations.

WAAS - The U.S. WAAS supports over 5461 ends of runways and hundreds of heliport/helipads in the U.S. National Airspace System (NAS). As of May 30, 2013, the WAAS supports:

  1. 3,123 Localizer Performance with Vertical guidance (LPV) procedures.
  2. 5,663 Lateral Navigation (LNAV) procedures.
  3. 3,003 LNAV / Vertical Navigation (VNAV) procedures published.
  4. 2,046 LPVs published to non-ILS runways.
  5. 421 Localizer Performance (LP) procedures.

There are now more than twice the numbers of WAAS-enabled LPV procedures as there are Category I ILS approaches.

The FAA is currently in Phase III of a four-phase WAAS program life cycle. WAAS has completed the operational integration of a new Geostationary Earth Orbit (GEO) satellite (Inmarsat 4F3-PRN 133). Future Phase III improvements underway include technology refresh and algorithmic improvements to increase service availability.

The U.S. SBAS expansion into Canada and Mexico was achieved with the integration of nine international wide-area reference stations (WRS) into the WAAS network. As of May 2013 Canada has published 147 LPVs serving 81 Airports with plans for more to follow. Mexico has announced plans to publish LPV procedures in the near future.

EGNOS - The first pan-European satellite navigation system. EGNOS Open Service was declared on October 1st 2009, supporting multimodal applications in non-aviation domains. Later on March 2nd 2011, EGNOS Safety of Life (SoL) service was declared operational, enabling the publication of LPV procedures over Europe. As of May 2013, there are 137 procedures based on EGNOS across Europe, supporting LPV and APV Baro approach operations. Nowadays, the publication of LPV procedures is very active, increasing the number continuously. Implementation of LPV-200 Service Level is planned for 2015. Up-to-date information is available http://www.essp-sas.eu/.

MSAS ? Japan’s Satellite Based Augmentation System using their MTSAT satellites. MSAS was declared operational in 2007 and provide horizontal guidance within the MSAS service volume. MSAS supports En Route, Terminal and Non-Precision Approach operations.

GAGAN ?is being implemented in three phases by the Airport Authority of India with the help of the Indian Space ResearchOrganization’s (ISRO) technology and space support. GAGAN plans to deliver RNP 0.1 as the first deployment milestone. The certification process is in progress and is expected to be completed by end of 2013. The second milestone is Approach with Vertical Guidance (APV) 1.0 over 90% of the Indian landmass. The timeline for completion and certification of APV 1.0 is first quarter of 2014. It is applicable to safety-of-life operations, and meets the performance requirements of international civil aviation regulatory bodies.

GAGAN offers free enhanced satellite navigation signals over India which is ten times more precise than GPS. All application domains which use positioning and velocity information can benefit from this improved accuracy: all transport modes through the management of infrastructure and the provision of geo-localised information, logistics, precision agriculture, civil protection and emergency management, mapping and land registry, fisheries, energy, management of natural resources, mining, Earth sciences, meteorology, the modelling of climate change, environment, justice and law enforcement, border control, etc.

SDCM ? Russia’s SBAS styled overlay for either GLONASS or GPS. SDCM plans to provide both horizontal and vertical guidance.

Although SBAS providers guarantee adequate service provision only in their nominal service volumes, SBAS broadcast signals will be available anywhere in their respective GEO footprints. This fact, together with the fact that EGNOS/GAGAN/MSAS/WAAS intermediate regions are not covered by any other SBAS system, has fostered debate about the possibility of providing a minimum service level in the intermediate region by means of SBAS interoperability.

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