ASAS TN Third Workshop, April 2004, Toulouse 1 ASAS Implementation in Avionics Pierre GAYRAUD Thales Avionics in collaboration with ACSS

ASAS TN Third Workshop, April 2004, Toulouse 2 Content ASAS functions to implement ADS-B-out ADS-B-in EUROCONTROL ASFA study ASAS-ACAS relationship Surveillance data processing AEEC Equipment standards Conclusion

ASAS TN Third Workshop, April 2004, Toulouse 3 ASAS functions to implement ADS-B In Rx ADS-B Out Tx HMI Aircraft data Message Processing Applications ADS-B-Out ADS-B-In

ASAS TN Third Workshop, April 2004, Toulouse 4 ASAS Package I functions to implement ADS-B OutADS-B In Application categoryAircraft data ADS-B Tx ADS-B Rx Applica tions HMI Ground surveillance ADS-B-ACC, TMA, NRA, APT, ADD Airborne Situational Awareness ATSA-SURF ATSA-AIRB and Visual acquisition ATSA S&A ATSA-SVA surveillanceAirborne spacing ASPA-S&M, ASPA-ITP, ASPA-C&P

ASAS TN Third Workshop, April 2004, Toulouse 5 ADS-B out Transmitters Mode S 1090 ES link transmitters already on board –Mode S transponder (mandatory on all IFR aircraft in Europe as of 31/03/2005) The transmission of Extended Squitters is part of the standard (provided Registers are loaded) UAT and VDL Mode 4 transmitters –Tx/Rx boxes

ASAS TN Third Workshop, April 2004, Toulouse 6 ADS-B Out Data Data allowed to be broadcast are defined by the existing ICAO SARPS (at least for Mode S ES and VDL Mode 4) –Aircraft identification, horizontal position and altitudes, velocity The definition of Intents is not stable ADS-B raises new problems concerning the quality of the data –Instead of predetermined data characteristics (e.g. radar data), qualifiers are associated to the transmitted data according to the aircraft avionics capabilities (accuracy, integrity…) –The current SARPS requires transmission of an Horizontal Protection limit and uncertainty characteristics –There are plans to update SARPS (NIC, SIL, NAC…) for air-air applications (backwards compatibility for air-ground) –There are also works within RTCA about the transmission of additional quality data (continuity, latency) through a TQL (Transmit Quality level) => Standards not totally stable

ASAS TN Third Workshop, April 2004, Toulouse 7 ADS-B-In functions Surveillance layerApplications layer Data Link layer ASAS domain ACAS domain Common ACAS/ASAS Display TA/RA ACAS tracks TA/RA ACAS tracks CAS Logic ACAS Surveillance ADS-B TIS-B Surveillance Data Processing (A-SDPD) Own position Other Systems (MCDU, FMS, …) ASAS tracks ASAS tracks, Selected target, Guidance data Display Management ASAS Applications UAT VDL M4 Receivers Active reply Active Interro g 1090 Receiver ( DF1 7 /DF1 8)

ASAS TN Third Workshop, April 2004, Toulouse 8 Airborne Surveillance Functional Architecture (ASFA Study) EUROCONTROL ADS program has sponsored two teams Main outcomes –ASAS/ACAS relationship –Functional, performance and interface requirements for Surveillance Data Processing (or A-SDPD: Airborne Surveillance Data Processing and Distribution) –A-SDPD architecture Follow-on: A-SDPD prototype test on the ADS-B Validation Testbed (AVT) at EEC

ASAS TN Third Workshop, April 2004, Toulouse 9 ADS-B-In ASAS-ACAS relationship Common parts –ACAS and ASAS tracks have to be displayed consistently to the crew => A synthesis of ACAS and ASAS display tracks is necessary before display (one symbol per aircraft) –For Mode S ES, the 1090 receiver can be shared by ACAS and ASAS (ICAO SARPS have provision for) Interactions –ICAO has specified the ACAS « hybrid surveillance » –A-SDPD may use ACAS tracks to consolidate ASAS tracks

ASAS TN Third Workshop, April 2004, Toulouse 10 ADS-B-In ASAS-ACAS relationship But some principles have to be followed: –Independence is required by ICAO no ASAS-ACAS common failure cause (it could induce an infringed separation while preventing ACAS to detect dangerous geometry) => Separated ACAS and ASAS surveillance processing –Compatibility is required the operations of one system shall not degrade the performance of the other (e.g.: no increase of the TA or RA rates during manoeuvres supported by ASAS) –Interoperability is desirable ACAS « hybrid surveillance » decreases the 1090 interrogation rate (ICAO requirements prevent to jeopardize independence) Comparison of ASAS data with ACAS tracks improves the integrity of ASAS data without impacting the independence (comparison is used only when in agreement)

ASAS TN Third Workshop, April 2004, Toulouse 11 ADS-B-In ASAS-ACAS relationship Partitioning techniques (software and hardware) allow –The ASAS functions (A-SDPD, Applications, Display Management) to be hosted in a TCAS Computer –While fulfilling the independence conditions Advantages –Box count minimization (direct cost, weight, reliability, maintenance) –No new antenna required for ASAS (as far as 1090 ES is used) –Facilitates interactions between the two functions Some ASAS applications could require services from FMS => The TCAS Computer becomes the « Traffic Computer »

ASAS TN Third Workshop, April 2004, Toulouse 12 A-SDPD can receive 3 types of data –Directly through ADS-B links from the ADS-B capable surrounding aircraft –Via one or several TIS-B links for aircraft covered by each TIS-B + ACAS tracks from ACAS surveillance TIS-B UAT Via three potential links –Mode S extended Squitter –UAT –VDL Mode 4 VDL Mode ES Surveillance data processing Data link receivers TIS-B Surveillance Data Processing (A-SDPD) Objective: to provide display and applications with « clean » data

ASAS TN Third Workshop, April 2004, Toulouse 13 The ASFA study has analysed the functional aspect Due to the number of combinations « what-if » analysis have been performed Package I applications will not use the complete set of combinations (probably only 1090 ES, TIS-B ?) The main objectives is to provide the data integrity and continuity matching the applications needs Data sources (target position, altitude, velocity…) –The number of independent sources which can be used to increase the integrity is limited Horizontal position: ADS-B and ACAS (and in some cases TIS-B) Vertical data: no redundancy, only the altitude transmit by the target aircraft Surveillance Data Processing (A-SDPD)

ASAS TN Third Workshop, April 2004, Toulouse 14 Data links –Data link redundancy mainly improve continuity Applications –Differing requirements according to the considered applications –But not determined yet  Top down analysis required (On-going within the Requirement Focus Group)  Critical role of the 24-bit ICAO address, the only unique target aircraft identifier on which tracks correlation is based (subsequently the case of Mode A/C aircraft not adequately solved yet) Surveillance Data Processing (A-SDPD)

ASAS TN Third Workshop, April 2004, Toulouse 15 Track Management Data Distribution Data Management 1090 ES (ADS-B TIS-B) UAT (ADS-B TIS-B) VDL M4 (ADS-B TIS-B) + ACAS Application requests Surveillance Data Processing (A-SDPD) Display Applications

ASAS TN Third Workshop, April 2004, Toulouse 16 AEEC Equipment standards AEEC (Airlines Electronic Engineering Committee) is defining the preferred airborne architectures ASAS ACAS –SAI Committee: the best place for ADS-B-In is the TCAS Computer (turned it in a Traffic Computer) Ex: ACSS TCAS3000 –ISS Committee is working on ARINC 768 (Integrated Surveillance System) An architecture to simplify on-board surveillance installation: Benefiting from the partitioning techniques it is possible to add: Mode S Transponder, TAWS, WXR + Alarm and display prioritization because those functions display data on the ND and/or raise alarms => The Traffic Computer is the backbone of the ISS concept (Integrated Surveillance System) TAWS WXR Mode S Transponder

ASAS TN Third Workshop, April 2004, Toulouse 17 Conclusion The avionics of modern Air Transport Aircraft can accommodate Package 1 ASAS applications without any addition of boxes or antennas ADS-B-Out and ADS-B-In to be hosted –ADS-B-Out: by the Mode S Transponder –ADS-B-In: mainly by the TCAS computer (Traffic Computer) (2 when required by architecture considerations) It is the first step of the Integrated Surveillance System Don’t forget the system integration with the surrounding equipment (impact on EIS/CDTI, Warning systems, FMS…) Definition of standards not stable