Agenda Item 6 GNSS Development Status and Future Work Eric Chatre, EC/ESA Rapporteur Technical WG, GNSS Panel Thank you… Good morning… I am ... and member of ATMCP. The complete title of the presentation is: Need for the development of performance criteria and the concept of required total system performance (RTSP): It relates directly to the topics to be addressed under agenda item 3 of the Conference, but you will easily see connections with virtually all agenda items. Performance, including safety, provides a vehicle to discuss all aspects of Air Navigation from the planning stages to the monitoring of actual service delivery.

Outline GNSS Elements GNSS Performance Requirements Definition of parameters Relationship betweens parameters Integrity Principles GNSS Standards Future Work

GNSS Elements Core Constellations GLONASS GPS Augmentations ABAS GBAS IOR ABAS GBAS SBAS

Aircraft-Based Augmentation System (ABAS) Stand-alone technique implemented in user equipment/software No accuracy improvement, lateral guidance only Provides integrity based on consistency check Needs redundant satellite measurements (5 or more satellites in view with good geometry) Integrity only Performance and availability limited to some phases of flight

Satellite-Based Augmentation System (SBAS) Objectives Improve accuracy of GPS or GLONASS by providing corrections for Satellite errors : clock and ephemeris Ionospheric errors : model over a geographic area Provide integrity information Lateral and vertical guidance Improved availability,

Satellite-Based Augmentation System (SBAS) (cont.) Architecture Network of stations covering a wide area (e.g. continent) Transmission of information to users through geostationary satellites Coverage and Service areas Coverage : Wherever the geostationary signals are received Service : Wherever operations have been approved by States

SBAS Architecture GEO GPS Reference Stations Uplink Station SBAS Master Station Uplink Station GEO GPS SBAS Message

Ground-Based Augmentation System (GBAS) Objectives Improve accuracy of GPS or GLONASS by providing for each satellite a composite correction Satellite errors : clock, ephemeris correction valid locally Ionospheric errors : local correction Tropospheric errors : local correction Provide integrity information

Ground-Based Augmentation System (GBAS)(cont.) Architecture Ground Reference Station (typically 1 per airport) Transmission of information to users through a VHF data link (108 to 118 MHz) Coverage Approach area (ILS like coverage) Terminal area (positioning service)

GPS and/or GLONASS, GEOs Reference station and VDB GBAS Architecture GPS and/or GLONASS, GEOs User Reference station and VDB VHF DATA LINK

Aviation Performance Requirements for GNSS (signal-in-space) Phase of Flight Accuracy (95%) Integrity Risk Continuity Risk Availability En Route H: 3.7 Km 1x10-7/h 1x10-4/h to 1x10-8/h 0.99 to 0.99999 Terminal H: 0.74 Km NPA H: 220 m APV I H: 16 m V: 20 m 2x10-7/App 8x10-6/ 15s APV II V: 8m Cat I V: 6 to 4 m Cat II/III Surface Ops Under Development

Interpretation of parameters Accuracy : Characterize typical behavior of the system in presence of nominal error components Integrity : Limit risk of abnormal behaviour of the system due to errors resulting from system failures -Integrity Risk -Alert Limit -Time to Alert Continuity : Limit risk of losing the service unexpectedly Availability : Accuracy + Integrity [+ Continuity]

Relationship between parameters Integrity Accuracy Continuity Availability Availabilty -Vertical accuracy/integrity is usually the main driver -Decreases as accuracy increases -Decreases as alert limit gets smaller GNSS performance is variable : in time in space New approach to ensure integrity for all users -Protection Level concept

Integrity principles Protection Level < Alert Limit  No Alert User Computed Protection Level Probability 1-1.10-7 Computed Position Alert Limit Protection Level < Alert Limit  No Alert Protection Level > Alert Limit  Alert

GNSS Standards, Procedures, Guidance Material Standards and Recommended Practices (ICAO Annex 10, Vol I) GNSS NOTAMS and Phraseology (ICAO Annex 15, PANS-ABC Doc 8400, PANS- ATM Doc 4444) Procedure Design Criteria (PANS-OPS, Doc 8168) Geodetic Reference Datum and Data Base Requirements (ICAO Annexes 4,11,14 &15, WGS-84 Manual Doc 9674) Information and guidance on implementation (GNSS Manual) Industry Standards (RTCA and EUROCAE MOPS/MASPS)

Industry Standards The main actors are : The Documents RTCA in the US, Special Committee 159 EUROCAE in Europe, Working Group 28 The Documents Minimum Operational Performance Specifications (MOPS) Minimum Aviation System Performance Standards (MASPS) Existing Standards ABAS/Basic GNSS receiver : DO-208 / ED-72 / (J)TSO-C129A SBAS receiver : DO-229 C / TSO-145A/146A GBAS Cat I receiver : DO-253A Multi-Mode Receiver including GBAS : ED-88A

Future Work Evolution of currently standardized GNSS elements GPS modernization with additional civil signal on L5 frequency (1176.45 MHz) GLONASS modernization (GLONASS K) with additional civil signal in the 1164-1215 MHz band Extention of SBAS standards to accomodate new signals Extention of GBAS standards to accomodate new signals and cover Category II/III and surface operations

Future Work (cont.) New GNSS elements GALILEO system with 3 civil signals and a dedicated integrity service Ground-Based Regional Augmentation System (GRAS)