Transcript WAAS Research at Stanford University

Global SBAS Status
Satellite Based Augmentation System (SBAS)
Interoperability Working Group (IWG)
June 2013
June 2013
Agenda
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Background
Benefits
Interoperability
System Status
System Evolution
Issues
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SBAS Background
• Satellite Based Augmentation System (SBAS) provides the
accuracy, integrity, service continuity and availability needed to rely
on Global Navigation Satellite System (GNSS) navigation for all
phases of flight, from en route through Category I approach
• SBAS technology provides the opportunity to cover very large areas
of airspace and areas formerly not served by other navigation aids
• SBAS adds increased capability, flexibility, and often, more costeffective navigation options than legacy ground-based navigation
aids
• SBAS can be used in many non-aviation applications
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SBAS Background
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International Civil Aviation Organization (ICAO) Standards
And Recommended Practices (SARPs) provides overarching
standards and guidance for Global SBAS implementation
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SARPs criteria define the SBAS standards for Approach with
Vertical guidance (APV) as being a stabilized descent using
vertical guidance
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SBAS Interoperability Working Group (IWG) is the forum for
SBAS service providers to assure common understanding and
implementation of the SARPs
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IWG forum allows coordinated development of
interchangeable avionics technology designed to easily
transition from one SBAS region to another
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SBAS Benefits
• SBAS service is available for free
• SBAS enables Performance Based Navigation (PBN) to
improve efficiency, capacity, and reduction of environmental
impacts and is the lowest cost enabler for Required Navigation
Performance (RNP)
• SBAS is an enabler for Federal Aviation Administration (FAA)
Next Generation Transportation System (NEXTGEN) and the
European Commission (EC) Single European Sky Air Traffic
Management Research (SESAR)
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SBAS Benefits
• Dual-frequency SBAS will support increased service
availability during ionospheric storms
• SBAS supports the decommissioning of ground-based Navigation
Aids (NAVAIDs)
• SBAS benefits extend beyond aviation to all modes of
transportation, including maritime, highways, and railroads
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SBAS Benefits – En Route
• SBAS is considered a primary navigation system
• SBAS allows for Receiver Autonomous Integrity Monitoring (RAIM)
check elimination
• SBAS supports Area Navigation (RNAV) and RNP
– SBAS enables all RNAV requirements for implementation of 'T' and 'Q' routes
• SBAS allows the flexibility to design more efficient airspace and
instrument procedures
• Significant reduction in track dispersion
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SBAS Benefits - Terminal
• Supports Trajectory Based Operations (TBO)
– 4-D Operations (Continuous Descent Approach (CDA))
– Significant reductions in fuel consumption
• Significant reduction in track dispersion
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SBAS Benefits - Approach
• Provides Category I (CAT I) vertical guidance at any
qualifying runway
– Localizer Performance with Vertical guidance (LPV)
– SBAS service does not require the installation or maintenance of
ground-based landing system navigation aids
• SBAS provides immunity to improper setting of aircraft
barometric altimeters
• SBAS is immune to barometric and temperature fluctuations
• Positive guidance RNP 0.3 across service areas
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SBAS Interoperability - SARPs
• ICAO SARPs Annex 10 and Aviation Standards supports
interoperability amongst SBAS service providers
– Supports seamless transition from one SBAS service area to another
SBAS service area
– Multi-constellation SBAS enabled by establishment of up to four core
GNSS Constellations:
• Global Positioning System (GPS), United States (US), operational
• Global Navigation Satellite System (GLONASS), Russia, operational
• Galileo, European Union (EU), expected operational by 2014
• BeiDou (COMPASS), China, SARPs development initiated May 2012
– Provides continued support to legacy single frequency users by
ensuring backward compatibility
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SBAS Interoperability - IWG
• SBAS IWG objectives established to support technical
interoperability and cooperation
– Objective 1: Harmonize SBAS modernization plans
– Objective 2: Forum for discussion on SBAS standards
– Objective 3: Harmonize technical improvements from operations and
users feedback
– Objective 4: Research and Development (R&D) cooperation on key
SBAS technologies
– Objective 5: Support joint SBAS promotion
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SBAS Status:
Operational Systems
• Wide Area Augmentation System (WAAS) – United States
– Operational since 2003
– Supports en route, terminal and approach operations
• CAT I-like approach capability (LPV-200)
• Multi-function Transport Satellite (MTSAT) Satellite-based
Augmentation System (MSAS) - Japan
– Operational since 2007
– Supports en route, terminal and non-precision approach operations
• European Geostationary Navigation Overlay Service
(EGNOS) – European Union
– Open Service was declared in October 2009
– Safety-Of-Life Service has been operational since March 2011
– Supports En Route, Terminal and Approach operations
• APV-1 (LPV equivalent) operational capability
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Current SBAS Performance
LPV Service (vertical guidance as low as 200’)
WAAS
EGNOS
Sources and additional detail:
• WAAS LPV Coverage (http://www.nstb.tc.faa.gov/24Hr_WaasLPV.htm)
• EGNOS LPV Coverage (http://egnos-user-support.essp-sas.eu/egnos_ops/node/975)
• MSAS (http://www.nec.com/en/global/solutions/cns-atm/navigation/msv.html)
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MSAS
(Note: Vertical Protection Level
Display is shown, but verticallyguided operations not yet
authorized.)
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Current SBAS Performance
Non-approach Operations (such as RNP 0.3)
WAAS
EGNOS
MSAS
(Horizontal Protection
Level Display)
Sources and additional detail:
• WAAS (http://www.nstb.tc.faa.gov/24Hr_WaasRNP3.htm)
• EGNOS (http://egnos-user-support.essp-sas.eu/egnos_ops/service_performances/global/NPA_availability)
• MSAS (http://www.nec.com/en/global/solutions/cns-atm/navigation/msv.html)
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SBAS Status:
Developing Systems
• Global Positioning System (GPS) Aided Geostationary Earth Orbit
(GEO) Augmented Navigation (GAGAN) - India
– In development with plans for horizontal and vertical guidance
– Final Acceptance Testing planned in 2012
• System of Differential Correction and Monitoring (SDCM) - Russia
– In development with plans for horizontal and vertical guidance
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SBAS Evolution
• GNSS Dual Frequency Operations
– Increases SBAS availability and performance by direct mitigation of
ionospheric signal delay
– Improves robustness against unintentional interference
• SBAS Service Provider Objectives
– Avionics manufacturers to support multi-constellation/multi-frequency
avionics as flight-certified navigation solutions
– Evaluate inclusion of additional GNSS constellations in SBAS such as
Galileo and Global Navigation Satellite System (GLONASS)
– Provide continued support to legacy L1-only users
– Support cooperative development of future SBAS standards
The slides that follow show a progression of scenarios in which combined SBAS coverage can
provide LPV-200 service. These scenarios are based on a generalized set of assumptions across
all systems and may not represent exact individual SBAS service levels.
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Current Reference Networks
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Current Coverage
LPV-200 Service Availability
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Current Plans for
Expanded Reference Networks
•WAAS
•EGNOS
•MSAS
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Improved Single
Frequency Coverage
•WAAS
•EGNOS
•MSAS
LPV-200 Service Availability
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Dual Frequency Coverage
(WAAS, EGNOS, MSAS)
•WAAS
•EGNOS
•MSAS
LPV-200 Service Availability
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Reference Networks with GAGAN
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Dual Frequency Coverage
(with GAGAN)
•WAAS
•EGNOS
•MSAS
•GAGAN
LPV-200 Service Availability
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Reference Networks with
GAGAN and SDCM
•WAAS
•EGNOS
•MSAS
•GAGAN
•SDCM
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Dual Frequency Coverage
(with GAGAN + SDCM)
•WAAS
•EGNOS
•MSAS
•GAGAN
•SDCM
LPV-200 Service Availability
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Expanded Networks
•WAAS
•EGNOS
•MSAS
•GAGAN
•SDCM
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Dual Frequency, Expanded Networks
LPV-200 Service Availability
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Dual Frequency +
Second Constellation (Galileo)
•WAAS
•EGNOS
•MSAS
•GAGAN
•SDCM
LPV-200 Service Availability
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Dual Frequency, Dual GNSS,
Expanded Networks
LPV-200 Service Availability
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Issues Being Addressed
• Seamless transition between SBAS service areas
– Evaluating transitions between SBAS and RAIM, along with transitions
between two SBASs, and between SBAS and GBAS
• Common interpretation of standards amongst SBAS developers
– Established a work plan for development of a definition document to
support a dual-frequency, multi-constellation user
• Currently Limited Global Coverage
– Global coverage to be expanded with addition of GAGAN and SDCM
– Availability of worldwide LPV-200 service expected with addition of a
second frequency, extended networks and additional GNSS constellations
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Conclusions
• Single Frequency SBAS offers significant benefits within
covered service areas
• Dual Frequency extends coverage outside reference
networks & allows LPV operation in equatorial areas and
during ionospheric storms
• Expanding SBAS networks into southern hemisphere would
allow global coverage of land masses
• Additional GNSS constellations allow even greater coverage
with fewer stations
• Multiple constellations enable development of
interchangeable avionics technology
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