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Most Probable Satellite Communications Operating Concept for ECAC and other regions of the world

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Title: Most Probable Satellite Communications Operating Concept for ECAC and other regions of the world


1
Most Probable Satellite Communications Operating
Concept for ECAC and other regions of the world
  • Presented by Philippe Renaud
  • Prepared by Phil Platt
  • ICAO AMCP WG-C
  • 27-30 May 2002

2
European Civil Aviation Conference (ECAC) Member
States
3
Communications Problems
  • In certain parts of the world (e.g. Europe) air
    traffic growth will outstrip communication
    resource in the VHF band.
  • New technologies are being considered in the
    timeframe of 2010-2015 to complement VHF systems
  • Satellite communications could be a possibility
    but only with improved performance over current
    AMSS
  • A lower cost satellite communication system would
    benefit many other areas of the world too

4
Predicted Traffic growth in Europe
5
Worldwide air traffic
6
Inmarsat Global beams
7
MTSAT - Japan
8
European spot beam
9
Limitation of current AMSS
  • Designed to meet full range of users leading to
    more complex system design
  • Shared use of spectrum between safety and
    non-safety services
  • Cost of aircraft installation and avionics
  • Large GESs leading limited options for
    communications service provision
  • Quality of communication service - transfer
    delays
  • Communication costs

10
A new satellite system ?
  • Oh no not more technology !
  • Havent we got enough satellite communications
    systems e.g.
  • Inmarsat Aero systems H, H, I, L, C, Mini-Aero,
    Swift64
  • MTSAT (Japan)
  • Boeing Connexion
  • Iridium
  • Globalstar
  • .

11
Safety related communications
  • Yes there are many satellite technologies around
    but they are designed to support shared use
  • Some support AAC, APC - some may support AOC and
    ATSC (e.g. Aero H)
  • No system supports only AMS(R)S
  • Previous experience has shown that reliance on a
    shared business case can cause problems
  • Where safety and regularity of flight
    communications are to be carried by a
    communications system specific measures must be
    put in place to safeguard them

12
Requirements
  • High levels of availability, reliability and
    continuity required for safety and regularity of
    flight communication
  • ATS
  • Voice
  • Data
  • AOC
  • Voice
  • Data
  • Ranked on priority basis

13
ATSC Voice
  • ATSC voice is main form for executive control
    today
  • There will be increased use of data link in the
    future but voice will be required at least in the
    foreseeable future
  • ATSC use of data link requires new investment in
    ATS system on ground - voice is already there.
  • VHF RT is the main means of communications in
    higher density airspace where there is a ground
    infrastructure

14
ATS Data Link Services
  • ATC Communications Management Service (ACM)
  • Departure Clearance Service (DCL)
  • ATC Clearances and Information Service (ACL)
  • Controller Access Parameters Service (CAP)
  • Downstream Clearances Service (DSC)
  • Pilot Preferences Downlink Service (PPD)
  • Flight Plan Consistency Service (FLIPCY)
  • Dynamic Route Availability Service (DYNAV)
  • Dynamic Route Availability Service (DYNAV)
  • Data Link Operational Terminal Information
    Service (D-OTIS)
  • Data Link Runway Visual Range (D-RVR)
  • Data Link Logon (DLL)
  • Common Trajectory Co-ordination (COTRAC)
  • Data Link SIGMET Service (D-SIGMET)
  • System Access Parameters Service (SAP)

15
AOC Applications
  • Voice
  • assumed to be continued to be required although
    expected to decline
  • Data Link
  • Flight Operations - a few examples of safety and
    regularity of flight applications
  • Access to Flight Information services (Weather,
    NOTAM)
  • Weight Balance
  • Performance Data
  • Maintenance
  • Aircraft condition monitoring

16
New Satellite System (1/2)
  • Desirable Features
  • Those identified in NGSS SARPs including
  • Tailored requirements - safety and regularity
    traffic only i.e. priority 1 to 6 in Article 44
  • dedicated AMS(R)S spectrum
  • Replicate and improve on existing systems
  • Voice - VHF RT like with party-line and quick
    access
  • Data - point-to-point and broadcast
  • Optimised channels
  • tailored to meet the AMS(R)S requirement only
    until at least 2020 and possibly longer
  • Designed to provide required level of performance
  • use redundancy in critical communications path

17
New Satellite System (2/2)
  • Desirable Features
  • Ground Earth Station
  • able to reuse existing AMSS infrastructure
    wherever possible
  • allows possibility to use GESs with smaller
    antennas
  • greater flexiblity in deployment e.g. at ATCC or
    airline sites
  • Aircraft Earth Station
  • smaller due to limited design goal
  • low power, cheaper
  • Spectrum Efficiency
  • maximise frequency reuse
  • specific protocol to carry short frequent data
  • efficient mapping of user data to satellite
    physical link

18
Satellite Data Link System
  • SDLS is attempting to meet the desirable features
  • a tool-box of good ideas
  • can pick any or all of the tools to for a new
    system
  • ESA has sponsored a considerable amount of design
    effort to match technology with perceived
    requirements
  • a lot of work by satellite system manufacturers
  • contribution to the input to a possible open
    standard for aviation use
  • Development of a  demonstrator  underway

19
Key features of SDLS (1/2)
  • Multiple Access Scheme
  • Synchronous CDMA in the fixed to mobile
    direction
  • Quasi Synchronous CDMA in the mobile to fixed
    direction
  • Aircraft Earth Stations
  • New CDMA modems being developed
  • Low cost solutions
  • Space Segment
  • MSS geostationary satellites at L-Band have
    already been deployed worldwide and hence are
    fundemental building block
  • Ground Earth Stations
  • Ku or C-Band depending on satellite feeder links

20
Key features of SDLS (2/2)
  • Services
  • Voice service (point to point and Party Line) 
  • Data service including broadcast and polled
  • Network Architecture
  • Capability for decentralised satellite access
  • Satellite Diversity
  • Asumed to be required to meet availability
    requirements
  • Equipment Redundancy
  • For both airborne and ground is part of the
    design
  • Communication Resource Management
  • Fixed and demand assignment, handling of priority
    levels

21
Ground Earth Stations
  • Two main types of feeder links
  • C-band
  • currently used by Inmarsat GESs on global and
    spot beams. Requires large antennas but the
    infrastructure is there and will be for the
    foreseeable future to support maritime services
  • Ku-band
  • allows the use of smaller (cheaper) GESs. Could
    be deployed at or near ATC centres or airline
    operational control centre
  • Ku-band is more subject to atmospheric
    disturbance than C-band - has to be taken into
    account in design
  • Only Ku-Band VSATs practically allow highly
    decentralised access

22
CDMA channel structure
Up to 255 CDMA channels per subband
23
Satellite Protocols
  • Reuse features of AMSS e.g.
  • Reliable Link- type service
  • AMSS strategy for priority, reference number
  • Data rate determined by type of satellite beam
    size
  • Minimum data rate in global beam
  • Basic channel rate is 6.8kbps - in global beam
    (determined by vocoder)
  • Short message data throughput is 1.35kbps
  • Long message data throughput is 2.4kbps
  • Spot beams increases rate at least 4 times.
  • Broadcast capability - ground to air

24
Voice service
  • Vocoder rate of 4.8kbps - may be the same as AMSS
  • Full duplex circuit mode service for normal use
  • suitable for AOC and some ATS applications
  • Special feature to emulate ATS RT
  • party-line feature - allows rebroadcast of
    messages to other aircraft
  • requires dedicated channel per sector
  • synchronous CDMA - no signal acquisition time

25
Satellite diversity
  • Satellite diversity could be required due to -
  • shielding of the aircraft antenna by the
    structure of the aircraft
  • failure of the satellite system
  • This requires on the ground -
  • one antenna for each satellite in view by the
    GES,
  • one spare GES antenna to ensure the reliability
  • Pre-assigned spectrum for each satellites

26
Satellite diversity
27
Aircraft Earth Stations
  • Simple and cheap
  • isotropic antenna
  • low RF power - no forced air cooling requirements
  • single transmit channel per AES
  • need 2 AESs per aircraft to achieve redundancy
    requirements
  • Direct data inputs for Polling Services e.g. A429
  • Interfaces to CMU/ATSU and voice distribution
    system

28
Aircraft Installation
29
Initial Deployment in ECAC
30
Ground architecture
31
Other deployment options
  • Whilst a solution based on global beams is a
    practical early solution (maybe preferred in
    ECAC area), other options are possible
  • Incremental flexible deployment can be provided
    through the use of spot beams where required
  • This could be an attractive first step in some
    areas of the world e.g. where there is not a well
    developed terrestrial infrastructure

32
Later deployment in ECAC
33
Ground Architecture
34
SDLS Demonstration Programme
  • SDLS Programme Phases
  • Key system performance demonstrator with AESs on
    ground (on-going with targeted completion third
    quarter 2002)
  • 2 AESs
  • 2 GESs - Ku band
  • ATS/AOC application emulation
  • EMS satellite
  • Evaluation with airborne avionics and the
    participation of ATSPs and airlines is in the
    planning stage

35
Institutional aspects
  • Standardisation
  • new satellite systems capability needs to be
    standardised for worldwide operation
  • confirm that NGSS SARPS are appropriate - seem so
    at initial review
  • Access control to space segment - who, how ?
  • Use of AMS(R)S spectrum with many service
    providers
  • GES operators
  • detailed technical standards
  • co-ordination between them e.g. use of codes,
    hand-overs, etc

36
Business Issues
  • Technically SDLS looks possible but there is a
    need to clarify business drivers
  • Targeted at AMS(R)S therefore has to be paid by
    ATSPs and airlines only e.g. no APC traffic
  • However it is not vulnerable to market failure
  • Benefits must come from cost saving
  • do nothing cases must be considered
  • compare technology solutions
  • Cost must be minimised

37
Issues for further consideration
  • Data rate
  • Lowest rate assumed acceptable - need to confirm
    (e.g. AOC)
  • Use of Polling Service
  • How is it used in practice ? Who controls the
    service and shares the data ?
  • Efficient use of satellite physical link
  • need optimise the mapping of user data onto RF
    link
  • ATSC voice service
  • design of human interface for access
  • party line acceptance

38
Conclusions (1/3)
  • Satellite based communication system have
    advantages for aviation
  • wide coverage capability
  • could overcome need for terrestrial
    infrastructure development in some areas of the
    world
  • traditionally thought of as oceanic and remote
    areas only but with improved performance and
    lower cost can be considered for higher density
    airspace
  • Advanced design concepts seem to show that higher
    service quality levels than AMSS are achievable
    with proven technology
  • can draw on AMSS experience and institutional
    arrangements
  • ability to enable new service provision
    possibilities

39
Conclusions (2/3)
  • Technical design concepts are well advanced in
    SDLS but still open to refinement
  • Finalisation of design in consultation with
    aviation community
  • Institutional arrangements
  • standards development - SARPS, MASPS, MOPS, etc
  • can draw on NGSS work already undertaken
  • Business case
  • costs should be lower due to specific AMS(R)S
    goal
  • better define the benefits including do
    nothing  option

40
Conclusions (3/3)
  • Recommendation on next steps in WG-C
  • Contribute to the production of a global
    operating concept to augment the ECAC Operational
    Concept
  • Contribute to the development of a design
    definition document
  • To liaise with AMCP WG-F to ensure the
    availability of adequate AMS(R)S spectrum
  • Address in due time the development of a Manual
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