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Index Introduction GBAS Overview GBAS CAT-I Services GBAS Implementation
Introduction Subject These slides presents a brief introduction to the Ground Based Augmentation System (GBAS) concepts, system architecture and operational benefits. Objectives Introduce the attendants to GBAS and how this system is being hosted by most of European countries as an different choice to ILS.
Index Introduction GBAS Overview GBAS CAT-I Services GBAS Implementation
GBAS Overview: Concepts Definition A Ground-Based Augmentation System (GBAS) is a civil-aviation safety-critical system that supports local augmentation (at airport level) of the primary GNSS constellation(s) by providing enhanced levels of service that support all phases of approach, landing, departure and surface operations. The GBAS is intended primarily to support precision approach operations. Main Features LocalaugmentationtoGNSSthatcoversaradiusofapprox.30km on the airport area Satellite-based precision approach and landing system Provides aircraft with very precise positioning guidance (horizontal and vertical), especially critical during the approach and landing phase of flight Provides safety and cost benefits to airlines, airports and air navigation service providers GBAS Ground Station (Toulouse, France)
GBAS Overview: System Architecture (I) System Architecture The main components of a general GBAS architecture are: GBAS Ground Subsystem: Consists of all the different equipment installed at the airport Reference Receiver Subsystem: Reference Receiver + Antenna GBAS Ground Facility VHF Data Broadcast(VDB) Subsystem GBAS Aircraft Subsystem: Consists of all the different equipment installed on board of the aircraft Multi-Mode receiver ILS/VOR antennas GNSS Satellites Subsystem: Consists of the GPS satellites, which transmit ranging signals and navigation messages RR + RRA and VDB Antenna (Málaga, Spain) Honeywell Processor Subsystem (Atlantic City, EEUU)
GBAS Overview: System Architecture (II) How it works? Signals from GPS satellites are received by the GBAS GPS Reference Receivers GBAS Ground Facility, using GPS data received by Reference Receivers, measure errors in GPSprovided position computing each satellite s pseudorange The GBAS Ground Facility produces a GBAS correction messages which includes as well integrity parameters and approach path information The VHF Data Broadcast (VDB) transmitter broadcasts the GBAS messages throughout the GBAS coverage area (approximately a 30 kilometer radius) to avionics in GBAS-equipped aircraft. The GBAS equipment in the aircraft uses the corrections provided on position, velocity, and timetoguidetheaircraftsafelytotherunway Airport GBAS Scenario
GBAS Overview: System Architecture (III) How it works? GBAS Basic Architecture
GBAS Overview: System Architecture (IV) Actors and Systems changes
GBAS Overview: System Architecture (V) Summary of key operational changes with GBAS For the pilot xls concept minimizing training. GLS used in phraseology and cockpit For the controller GLS/GBAS phraseology New procedures To support missed ILS/GBAS CAT-I operations at the airport Fall back procedures to address GBAS failure required To facilitate switching runways or shortening approach path at some airports For the maintenance staff Responsible to handle high integrity data and enable/disable GBAS approaches For the approach designer Responsible for the creation of FAS data block and providing it to the maintenance staff with a high integrity level. Note: Due to the ILS look alike concept, no change to the final approach capture and missed approach procedure has been considered
GBAS Overview: System Performances (I) System Performances GBAS approach criteria same as ILS GBAS operating minima same as ILS
GBAS Overview: System Performances (II) System Performances A GBAS CAT I Ground Subsystem develops performances similar to ILS A single GBAS Ground Subsystem can cover single/multiple airport/s area/s, which decreases the infrastructure costs in the airport In the near future, GBAS CAT II/III using multi-constellation will allow lower decision heights. Category DH RVR CAT I 60 m (200 ft) 550 m CAT II 200 ft >DH 100 ft 350 m CAT III A CAT III B < 100 ft or no DH < 15 m or no DH 200 m 200>RVR 50 m CAT III C No minima No minima
GBAS Overview: System Performances (III) GBAS Approach Service Type GAST-A: for operations to APV I performance GAST-B: for operations to APV II performance GAST-C: for operations to CAT I performance level GAST-D: for operations to CAT III performance (with specific aircraft integration assumptions) GAST-E(TBD): either CAT II performance or L5/E5 CAT III with integration assumptions GAST-F(TBD): planned for multi-constellation, multi-frequency CAT III performance level Note: GAST (GBAS Approach Service Type) future SARPS designation, used here for clarity, not in current standards
GBAS Overview: Operational benefits (I) Airlines Benefits Fuel savings, noise abatement and reduced emissions from efficient, flexible flight path Less flight disruptions and associated costs caused by ILS interference Greater precision guidance for improved safety Minimal pilot training(common procedures with current ILS make pilot training easier and reduce human factors associated with new flight deck technology) Cockpit view of the GBAS approach to Toulouse
GBAS Overview: Operational benefits (II) Airport Benefits 1 GBAS Installation where multiple ILS would be required Improved airport capacity from accurately guided simultaneous operations Flexibility in GBAS station location, unlock valuable airport land and alleviate traffic restrictions which are otherwise required to protect ILS signals from interference sources Improved airport access, even when ILS cannot be installed for terrain or economic reasons
GBAS Overview: Operational benefits (III) ANSP Benefits Reduced traffic delays and congestions as a result of more accurate and efficient and predictable approaches Reduced capital investment cost and lower on-going maintenance, as one GBAS covers all runways, compared to one ILS installation per one runway end Flexibility to add or change Final Approach procedures without changing the system configuration Easier and less frequent flight inspection than ILS Continued operations even during routine flight inspections or airport works Airline Flight Efficiency Predictability Safety Minimal Pilot Training Airport Throughput Accessibility Siting Flexibility Effective Use of Airport Land ANSP Safety Efficiency Reduce Delays Savings GBAS Benefits Summary
GBAS Overview: Specifications Comparison Specifications GBAS ILS SBAS Type of Approaches CAT-I, future CAT-II/III CAT-I, II and III Non Precision Approaches Number of Approaches 26 per Ground Station 1 Unlimited Aircraft Equipment GLS avionics ILS receiver Airport Equipment Coverage Ground Station,2-4 Reference Receivers/Antennas, VDB Transmitter, Lighting System All runways of GBAS equiped airport LightingSystem,GlideSlope, Localizer One runway threshold GPS/SBAS Receiver, Approach Database Lighting System(GPS NPA) Global(limited by the installed reference stations) Equipment/Installation Cost GBAS station cost ~ 2 times ILS cost $1,000M per country Maintenance Annual Cost Half price per station compared to ILS $50M-$100M per country
Index Introduction GBAS Overview GBAS CAT-I Services GBAS Implementation
GBAS CAT-I Services: Service volume Service Volume The GBAS coverage volume is defined as the region within which the system meets the accuracy, integrity and continuity requirements The minimum GBAS coverage to support each Category I precision approach, shall be as follows: LTP/FTP: Landing Threshold point GPIP: Glide Path Intersection Point GPA: Glide Path Angle HAT: Height Above Threshold Coverage Minimum Requirements
GBAS CAT-I Services: Signal-in-Space (I) GBAS Messages Types Message type identifier Message name Minimum Broadcast Rate Maximum Broadcast Rate 0 Spare - - 1 Pseudo range corrections For each measurement type All measurement blocks, once per frame (0.5s) 2 GBAS related data Once per 20 consecutive frames (10s) 3 Reserved for ground based ranging source 4 Final Approach Segment (FAS) data For each measurement type All measurement blocks, once per slot (0.0625s) Once per frame (0.5s) - - All FAS blocks once per 20 consecutive frames (10s) All FAS blocks one per frame (0.5s) 5 Predicted ranging source availability All impacted sources once per 20 consecutive frames (10s) All impacted sources once per 5 consecutive frames (2.5s) 6 Reserved - - 7 Reserved for national applications - - 8 Reserved for test applications - - 9-255 Spare. - -
GBAS CAT-I Services: Signal-in-Space (II) Message Type 1 Provides the differential correction data for individual GNSS ranging sources: Message information (time of validity, additional message flag, number of measurements and measurement type) Low-frequency information (ephemeris decorrelation parameter, ranging source ephemeris CRC and ranging source availability duration information) Satellite data measurement blocks (pseudo-range correction, range-rate correction, sigma pr_gnd, B values) Message Block Header Message Message Block CRC Message Information Low-Frequency Information Measurement Block Modified Z-Count Additional Message Flag Number of measurements Measurement Type Ephemeris Decorrelation Parameter Ephemeris CRC Source Availability Duration Ranging Source ID Issue of Data (IOD) Pseudorange Correction (PRC) Range-Rate Correction (RRC) σ pr_gnd & B1-B4
GBAS CAT-I Services: Signal-in-Space (III) Message Type 2 Contains the exact location reference for the Station corrections in WGS-84 coordinates. It also contains additional configuration data and for computation of a tropospheric correction. Message Block Header Message Message Block CRC Correction Reference GBAS Related Data GBAS Reference Receiver GBAS Accuracy Designator Letter GBAS Continuity/Integrity Designator Local Magnetic Variation Refractivity Index Scale Height Refractivity Uncertainty
GBAS CAT-I Services: Signal-in-Space (IV) Message Type 4 Contains the Final Approach Segment(FAS) Construction Data: DataSetLength:indicatesthenumberofbytesinthedataset FAS Data Block: contains the construction data for a Final Approach Segment. FAS Lateral Alert Limit/ Approach Status: The value of the broadcast lateral alert limit. FAS Vertical Alert Limit/ Approach Status: The value of the broadcast vertical alert limit. Data Content Bits used Range of Values Resolution ForNdatasets: Datasetlength 8 2 to 212 1 byte FASDataBlock 304 -- -- FAS vertical alert limit/approach status 8 0 to 25,4 m 0,1 m FAS lateral alert limit/approach status 8 0 to 50,8 m 0,2 m
GBAS CAT-I Services: Signal-in-Space (V) FAS Data Block Parameter Unit Range Bits Resolution Operation Type N/A 0-15 4 1 SBAS service Provider N/A 0-15 4 1 Airport ID N/A - 32 - Runway Number N/A 0-36 6 1 Runway Letter N/A - 2 - Approach Performance Designator N/A 0-7 3 1 Route Indicator N/A - 5 - Reference Path Data Selector N/A 0-48 8 1 Reference Path ID N/A - 32 - LTP/FTP Latitude deg ±90.0 32 0.0005 LTP/FTP Longitude deg ±180.0 32 0.0005 LTP/FTP Height m -512.0-6041.5 16 0.1 FPAP Latitude arcsec ±1.0 24 0.0005 FPAP Longitude arcsec ±1.0 24 0.0005 Approach Threshold Crossing Height (TCH) m or ft 0-1638.35m or 0-3276.7 ft 15 0.05 m or 0.1 ft Approach TCH Units Selector -- -- 1 -- Glide Path Angle(GPA) deg 0 90.0 16 0.01 Course Width at Threshold m 80.0-143.75 8 0.25 Length Offset m 0-2032 8 8 Final Approach Segment CRC -- -- 32 --
Index Introduction GBAS Overview GBAS CAT-I Services GBAS Implementation
GBAS Implementation Europe Roadmap 2010-2015 ILS remains as prime means of PA Gradual elimination of NPAs and replacement by APV (Baro or SBAS) CAT I GBAS is progressively implemented MLS as alternative 2015-2020 ILS remains a prime means CAT I GLS, SBAS LPV 200 and MLS are introduced and maintained when required CAT II/III GBAS multiconstellation/frequency becomes available Post 2020 ILS remains a significant source for PA Wide GLS use incl CAT II/III leading to decommissioning Cat I ILS CAT II/III ILS retained as backup for GLS Increased use of LPV based on GPS/Galileo/SBAS including G.aviation Source: ICAO
GBAS Implementation Implementation Steps GBAS Operations Successfully Implemented Service Approval Facility Installation Approval System Design Approval Flight Planning NOTAMS GLS Operation to Operational documentation (AIP ) ATC Training GLS procedures design & charting Technical Training Testing and Training ATC Procedures system update Maintenance & Support GBAS Equipment Installations
GBAS Implementation Regulatory Documents EUROCAE ED-114: Minimum Operational Performance Specification for Global Navigation Satellite Ground Based Augmentation System Ground Equipment to Support Category I Operations EUROCAE ED-95: Minimum Aviation System Performance Specification for a Global Navigation Satellite System GBAS to support CAT-I RTCA/DO-253C: Minimum Operational Performance Standards for GPS. Local Area Augmentation System Airborne Equipment RTCA/DO-246D: GNSS-Based Precision Approach Local Area Augmentation System (LAAS) Signalin-Space Interface Control Document(ICD) RTCA/DO-245: Minimum Aviation System Performance Standards for the Local Area Augmentation System(LAAS) ICAO SARPS, Annex 10, Volume I, 6th Edition 2006, including Amendment 84(GNSS SARPS)
GBAS Implementation Global Status GBAS Implementation status(http://flygls.net) European commitment to GBAS CATII/III implementation through SESAR GBAS Implementation in USA, Japan, Australia, Brasil and Russia: USA: Newark in July 2012 Houston in Spring 2012 Final goal: Working on CAT III Australia:first GLS operations (with restrictions) in June 2011 Planned GBAS projects in Korea GBAS Status World map (source: FlyGLS)
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