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WAAS Future and Evolutions

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Title WAAS Future and Evolutions
Edited by GMV
Level Basic
Year of Publication 2011
Logo GMV.png

The Wide Area Augmentation System (WAAS) is the United States Satellite Based Augmentation System. The programme, started in 1992, is being carried out by the Federal Aviation Agency (FAA)[1] and is specially developed for the civil aviation community.[2] The system, which was declared operational in late 2003,[3] currently supports thousands of aircraft instrument approaches in more than one thousand airports in USA and Canada.[4] WAAS service area includes CONUS, Alaska, Canada and Mexico.[5] The WAAS programme is continuously in evolution; two development phases have been already covered, a third is in progress, and there are plans to improve the capability of the system in parallel with the evolution of the SBAS standards towards a dual-frequency augmentation service.[6]

WAAS Future and Evolutions

The WAAS Development Phases are:[7][8][9][10]

  1. Phase I –Initial Operating Capability (IOC). Completed in 2003.
  2. Phase II -Full LPV Performance. Completed in 2008.
  3. Phase III -Full LPV-200 Performance. Planned for 2009-2013.
  4. Phase IV -Dual Frequency Operations. Planned for 2014-2028.

In Phase I, WAAS

  • Achieved Initial Operating Capability (IOC)
  • Provided LNAV/ VNAV/ Limited LPV Capability

In Phase II, WAAS provided:

  • Improved LPV availability in CONUS and Alaska
  • Expanded coverage to Mexico and Canada

Phase III, currently under development, implies the following changes:[7][10]

  • Technology refresh covering development, modifications, and enhancements in the system.
  • Steady state operations and maintenance, such as replacement of legacy WRSs, router upgrades,...
  • Space segment upgrades, with the broadcast of WAAS signal-in-space form a a third GEO satellite, Inmarsat AMR (PRN #133), since November 2010, complementing Galaxy 15 (PRN #135) and Anik F1R (PRN #138).
  • Begin GPS L5 activities: specifications, planning, definition of interfaces and standards, receiver development, etc.

For Phase IV, WAAS shall begin to operate with Dual Frequency (L1-L5). This would imply:[7][10]

  • Complete the transition to SBAS L1/L5 dual frequency service.
  • Provision of the SBAS-L1 single-frequency legacy service until 2028.
  • Maintain a robust, reliable, and sustainable LPV-200 capability.
  • Maintenance of the LPV-200 capability, paying special attention to its robustness and reliability.
  • High availability performance, with steady operations and smooth maintenance.
  • Improve service during severe solar activity.

In April 2015, the Federal Aviation Administration (FAA) has awarded a $103-million contract to the Raytheon Company to maintain the GPS Wide Area Augmentation System (WAAS). The company will develop a payload to be incorporated into a new geostationary satellite and two associated ground uplink stations to support the WAAS system within U.S. airspace. The WAAS GEO 6 payload will be hosted aboard a commercial host satellite in a geostationary earth orbit (GEO). The GEO 6 system, along with GEO 5 (under a contract awarded to Raytheon in 2012), will replace two WAAS GEO payloads that are approaching the end of their service leases. Projected launch of the WAAS GEO 6 payload will occur in the second quarter of 2017. The agency is in the process of converting WAAS from a single-frequency (L1) system to dual-frequency (L1/L5) operation. The FAA plans to sustain dual-frequency WAAS GEOs until at least 2044.[11]