""" " WIDE AREA

AUGMENTATION SYSTEM

WAAS

ADDITIONAL INFORMATION: https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/waas/

http://www.dtic.mil/dtic/tr/fulltext/u2/a495545.pdf

http://aviation.about.com/od/New-Technology/g/Wide-Area-Augmentation-System-Waas.htm

http://www.gps.gov/technical/ps/2008-WAAS-performance-standard.pdf

LOCATIONAL AVAILABILITYWAAS is available in North America and Hawaii.

WHAT IS WAAS?"WAAS is the North American satellite based augmentation system (SBAS). The system networks GPS broadcasting satellites, Wide Area Reference Stations (WRS), Wide Area Master Stations (WMS), Uplink Stations and Geostationary Satellites to provide corrections and integrity data to GNSS users for increased accuracy and reliability of GPS and GLONASS data. 1m Lateral Accuracy, 1.5m Vertical Accuracy - 95% of the time.[1] WAAS uses the Inmarsat-4 F3, Telesat's Anik F1R, and the Intelsat Galaxy 15 satellite.

HOW DOES IT WORK?Wide Area Reference Stations (WRS) collect GPS and GLONASS signals and relay this data to Wide Area Master Stations (WMS) for correction and integrity signal generation. Corrections and integrity data are then transmitted to geostationary satellites via uplink stations and broadcast to North American GNSS users with WAAS enabled GNSS receivers. Receivers use corrections to precisely compute their position, improving positional accuracy.

Users are alerted within 6.2 seconds of system unavailability or the transmission of hazardous or misleading information.[2]

COMMON SBAS APPLICATIONSCritical navigation situations such as:

• Aircraft Flight Path and Landing

• Precise Train Tracking

• Vessel Manoeuvres

• Oil Platform PositioningSBAS LIMITATIONS• System space segment exposed to space debris

and solar-storm threats

• Incomplete system coverage away from Geostationary satellite locations

• Not accurate enough for stringent regulations so more accurate systems are required to meet regulation. E.g. Local Area Augmentation System

SBAS BENEFITS• Highly Accurate Positioning • Easy to use • Significantly less expensive than similar systems • Limited infrastructure required • No airport-based system needed • Can compensate for lack of visibility • Can establish direct airborne routes

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1

Image Source: http://www.essp-sas.eu/

Image Source: http://www.nstb.tc.faa.gov/

Image Source: wikimedia.org [1] [2] Refer to reference sheet

Note:!GAGAN is the Indian Subcontinent SBAS

LOCATIONAL AVAILABILITY AND SERVICES EGNOS is available within Europe with expansion planned to Africa and the Middle East.

WHAT IS EGNOS? "European satellite based augmentation system (SBAS). It’s signals complement GNSS data to provide users with more precise positioning. Geostationary satellites supply users with corrections and integrity data that detail the reliability and accuracy of the positioning data. Consists of multiple ground stations and three geostationary satellites. The system uses the European Space Agency Artemis satellite and two Inmarsat-3 satellites. Achievable accuracy is estimated at 1.5m.[3]

HOW DOES IT WORK? EGNOS uses a series of Ranging and Integrity Monitoring Ground Stations (RIMS) throughout Europe to collect GPS and GLONASS signals. These signals are processed at Master Control Centres (MCCs) and sent to Navigation Land Earth Stations (NLES) that transmit the processed correct ions and integr i ty data to geostationary satellites for broadcast to European GNSS users with EGNOS enabled GNSS receivers. EGNOS was developed to be interoperable with other SBASs.

Geostationary satellites orbit at altitude of 36,000km.[4]

Users are alerted within 6 seconds of system unavailability or the transmission of hazardous or misleading information.[5] ADDITIONAL SBAS

APPLICATIONS • Scientific Applications - Geodesy

• Precision Farming

• Guidance of Agricultural Machinery

• On-Road Vehicle Fleet Management

• Precision Personal Mobile Navigation

ADDITIONAL INFORMATION: http://www.esa.int/Our_Activities/Navigation/The_present_-_EGNOS/

http://www.satellite-navigation.eu/

http://ec.europa.eu/enterprise/policies/satnav/egnos/

http://www.egnos-portal.eu/

http://www.gsa.europa.eu/

http://www.essp-sas.eu/

EGNOS provides three services:

Open Service - free positioning data to Europeans via enabled GPS receivers. Horizontal accuracy of 1–3 m and vertical accuracy of 2–4 m.[4]

Commercial Data Distribution Service - real-time raw data and processed EGNOS products made available for professional use. E.g. Signal integrity information and corrections for GPS L1 & L2 pseudo-range, GPS clock, satellite orbit, and Ionospheric conditions.[4]

Safety of Life Service - dedicated to users with stringent safety requirements. E.g. Aviation authorities - supports vertical and horizontal guidance for landing procedures within European airspace.[4]

"""" " EUROPEAN GEOSTATIONARY

NAVIGATION OVERLAY SERVICE

EGNOS

2

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Image Source: http://egnos-portal.gsa.europa.eu/

Image Source: http://html.rincondelvago.com/

Image Source: http://sherpa.essp-sas.eu/[3] [4] [5] Refer to reference sheet

Note:!GAGAN is the Indian Subcontinent SBAS