Title: Most Probable Satellite Communications Operating Concept for ECAC and other regions of the world
1Most 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
2European Civil Aviation Conference (ECAC) Member
States
3Communications 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
4Predicted Traffic growth in Europe
5Worldwide air traffic
6Inmarsat Global beams
7MTSAT - Japan
8European spot beam
9Limitation 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
10A 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
- .
11Safety 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
12Requirements
- 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
13ATSC 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
14ATS 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)
15AOC 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
16New 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
17New 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
18Satellite 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
19Key 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
20Key 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
22CDMA channel structure
Up to 255 CDMA channels per subband
23Satellite 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
24Voice 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
25Satellite 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
26Satellite diversity
27Aircraft 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
28Aircraft Installation
29Initial Deployment in ECAC
30Ground architecture
31Other 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
32Later deployment in ECAC
33Ground Architecture
34SDLS 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
35Institutional 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
36Business 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
37Issues 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
38Conclusions (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
39Conclusions (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
40Conclusions (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