1、Airbus work on VDL Mode 4,ICAO ACP Working Group C Meeting Toulouse 20-24 October 2003 WGC6/WP29,Airbus VDL Mode 4 background,VHF installations on airliners On over 20 different jet airframes, in service since 1954 Typically 3 or more makes/models of radio per airframe Analogue, digital & multimode,
2、 several variants per make/model Airline and government radios Over 63 000 000 flight hours worldwide, mainly since 1974 Europes prime source of airliner VHF safety, installation, problem identification and problem resolution expertise ICAO, EUROCAE/RTCA-EN & ARINC/AEEC standards participant CEC NUP
3、 II research programme participant CEC Data Link Roadmap Study participant ICAO ACP participant ICAO 11th ANC co-ordinator for ICCAIA EC VDL Mode 4 Airborne Architecture Study reviewer,Min. 35 dB isolation,Min. 50 dB isolation,Air transport aircraft VHF Comm. antennas,A320 shown A318, A319 & some B7
4、37s are shorter, but have same isolation,Co-site interference allowable up to 2 MHz each side, for opposite-side antennas,Co-site interference allowable up to 6 MHz each side, for same-side antennas,Intended receive frequency,Air Transport Aircraft VHF Com. Receiver sensitivity and selectivity,Full-
5、time sensitivity much better than the regulatory minimum,Frequency,Sens.,VHF Co-site interference is allowable and occurs,Occurs on voice & ACARS, mitigations ensure safety,NUP II VDL-4 work,NUP II is a surveillance-only programme does not address Comms. aimed at ADS-B-out/VDL-4 airline in-service t
6、rials by 2004 co-existing with VHF voice may not allow classic VHF Comm. mitigations. planned airline Service Bulletin issuance consequently discontinued Air Transport VDL-4 radios much more expensive than expected planned radio purchase consequently discontinued Consequently plan revised to trial a
7、 LFV-supplied VDL-4 radio, but only on an Airbus-operated flight-test aircraft LFV is looking for another solution for an airline in-service trial,Interference mitigation,Transmissions,Time,Irregular interference from voice & data occurs today,ATC voice messages can safely be repeated & understood,T
8、ransmissions,Time,Regular interference would occur from VDL ADS-Broadcast,ATC voice messages might not be repeated & understood,Existing voice mitigation measures might not be used with VDL ADS-Broadcast, unless surveillance is turned off,NUP II VDL Mode 4 initial trial,Initial aircraft ground trial
9、 installation Loaned non-air-transport (-power) COTS VDL-4 transceiver, transmitting ADS-B frequently on one frequency Connected to the VHF3 antenna, in lieu of the VDR3 transceiver Distant low-power handheld VHF & ATIS desired-signal transmitters VHF1 & VHF2 tuned to receive desired-signal transmis
10、sions No squelch breaks experienced due to VDL-4 when desired signal was not transmitted When desired-signal and VDL-4 test transmissions were active together, “metronome-like” clicks were heard On a number of desired-signal test frequencies Test results analysis is in progress,Datalink Roadmap Stud
11、y and ICAO ACP,Made available NUP II results that were available at the time Advised that Mode S ELS, EHS and ES would be the initial SSR surveillance and ADS-B air-ground & air-air media Advised that VDL-Mode 2 would be the initial air-ground medium Advised that core-area airlines, ANSPs and air-tr
12、ansport airframers were planning to use these media Expressed concern that VHF spectrum saturation would occur around 2013, dominated by safety-of-life voice use Expressed concern that VDL-4 service may add little to data efficiency, but be detrimental to spectrum availabilityproliferation of standa
13、rds, many core-area channels needed,ICAO ANC-11 with ICCAIA,Recommended that ICAO consider frequency planning consequences Consider real VHF radio performance Co-site interference within 6 MHz From VDL used for ADS-B Consider that surveillance & voice Are safety-of-life services Unavailability of ei
14、ther impacts service levels Consider VHF spectrum availability Poor in the core areas by 2013, due to voice Needed mainly for safety-of-life voice services ANC-11 recommended use of 1090ES for initial ADS-B implementation Without demurral (including Mongolia, Russia & Sweden) Recommended continued s
15、tandards work on UAT & VDL-4 For eventual future surveillance implementation, if spectrum available Did not recommend use for point-to-point communications Recommended use of already-implemented standard systems (e.g. VDL-2),Airbus views on VDL Mode 4,VHF is an undesirable spectrum for ADS-B, due to
16、 existence of the efficient, safe, inexpensive 1090 ES medium added high aircraft costs, co-site interference, poor core-area spectrum availability & need for several channels separated by 6 MHz from ATC voice VDL-4 was the only VHF candidate for ADS-B initial implementation Advantages claimed for V
17、DL-4 point-to-point datalink are not widely accepted, and likely outweighed by added standards proliferation Architecture of VDL Mode 4 Airborne Architecture Study adds complexity & vulnerabilities, compared with existing Would need much more safety studies VDL-4 was a good experimental medium Co-si
18、te interference is not a safety problem for voice, ACARS or VDL communications use,What next?,Airbus supports AEAs view that ADS-B VDL-4 work should be terminated Except for supporting existing experimental programmes Implementation resources should be used for 1090ES National surveillance aids can
19、impact airline safety Impact on VHF Comm. safety-of-life spectrum should be reviewed, prior to continuing VDL-4 Comm. Work VHF Comm. spectrum runs out around 2013 in core Europe We need to go up in spectrum for Comms & Surveillance UAT? 1030ES? Eurocontrols Newcom? Would STDMA protocols help significantly or hinder?,Thank you for listening any questions?,
