ZULFIQAR ALI MIRANI
CNS/ATMEVOLUTION
July 19, 2012
What’s CNS/ATM
CNS/ATM stands for
Communication
Navigation
Surveillance/
Air Traffic Management
Current Communication Environment
Air TrafficServices Unit
VHF Voice
NeighboringAir Traffic ServicesUnit
HF Voice
VHF Radio
HF Radio
Voice and Data
HF communication is not restricted by line-of-sight , but HF radiotelephony is noisy, uncertain and inefficient
Voice communication has slow rate of information transfer. Voice communication problems arise due to language skill or accent of controllers and pilots. Possibility of errors under transmission or comprehension High workload of a controller.
Limitations of the present communication systems
The lack of digital air-ground data interchange systems to support automated systems in the air and on the ground. Existing ground voice/ data network is performing poorly
VHF radiotelephony has interference problems VHF radiotelephony coverage is poor VHF frequency and channel congestion.
Voice
Data
VHF
HF
Current Air Navigation Environment
• The propagation limitations of current ground-based navigation systems.• No full coverage of VOR/DME beacons and others as well in many regions of the world
Limitations Of The Present Navigation Systems
En-route
• Accuracy limitations, that does not allow to use flexible routes and area navigationArea Navigation
• Limited capabilities of existing system ( ILS) concerning coverage, stability and accuracy Landing
Current SurveillanceEnvironment
Secondary surveillance radar mode A/C
Primary surveillance radar
VHF ground direction finder
Air Traffic Control
Voice positionreport
RadarSurveillance
• Overload of transponder under overlapped coverage of SSR (A and C modes).• Possibility of false interrogations and answers.
• Accuracy limitations connected with:- different errors of time delay estimation;- limited range and angle resolution.
Limitations of the present surveillance systems
Accuracy
SSR
• The propagation limitations of current line-of-sight primary and secondary radars.• No full coverage in many areas of the world.
Coverage
Current Environment of Communication, Navigation and Surveillance
Communication Navigation Surveillance
Ground-to -Ground Enroute Radars
Voice VHF, HF NDBVORDME
PSRSSR (Mode A/C)Data Telephone
Wire, AFTN
Air-Ground Landing Voice Reporting
Voice VHF, HF ILS VHF
Data Very limited
EVOLUTION OF CNS/ATM CONCEPT
In 1983, Special Committee on Future Air Navigation Systems (FANS) was established by ICAO Council
Task: to study, identify and assess new technologies, including satellite technology; and to make recommendations for the future development of navigation systems for civil aviation.
FANS committee submitted its report in May 1988.
FANS (Future Air Navigation System) - Initiative
The limitations of voice communications and the lack of digital air-ground data interchange systems to support automatedsystems in the air and on the ground
The difficulty of implementing present CNS systems and of operating them in a consistent manner in large partsof the world
The propagation limitations of current line-of-sight systems
Shortcomings into the current air navigation system
CNS/ATM Concept Approval
The concept of CNS/ATM, as suggested by FANS Committee, was adopted at the 10th Air Navigation Meeting held in September 1991 at Montreal, Canada.
The concept is a mix of the best use of satellite technology and the line-of-sight systems to achieve the desired goal of organized Air Traffic Management.
Air Traffic Management Structure
Air Traffic Management
Airspace Management
Air Traffic Services• Air Traffic Control• Flight Information Service• Alerting Service
Air Traffic Flow Management
Components
Communication
Navigation
Surveillance
Functions
Transition to CNS/ATM
Major elements of change
• from ground-based to satellite based systems;• from limited coverage to global coverage; and • from analog to digital (data) communication.
There will be a great change in the pilot-controller interaction.
Transition to the new system will be one of the largest undertaking ever carried out by the aviation community.
Key Technologies Involve
Data Communication Links• VDL, HFDL, Mode-S, SATCOM
Satellite Navigation • Global Navigation Satellite System
Automatic Dependence SurveillanceADS-B
• Satellite Communication, Navigation and Surveillance; and
• Data Communication
INSIGHT INTO CNS/ATM SYSTEM
Air Traffic Management
Elements of ATM
• Air Traffic Services (ATS)• Air Space Management (ASM)• Flight Operations (ATM related aspects)• Air Traffic Flow Management (ATFM)
Air Traffic Services
ATS is the prime element of ATM.
ATS Sub-elements:
• Alerting Services;• Flight Information Service (FIS); and• Air Traffic Control.
The main objectives of ATC services are to prevent collisions between aircrafts and between aircraft and obstructions on the maneuvering area and to expedite and maintain an orderly flow of air traffic.
Air Space Management
ASM is recognized as dynamic sharing of airspace by civil and military users.
Flight Operations
The ATM-related aspects of flight operations are an integral part of ATM in CNS/ATM systems.
Air Traffic Flow Management
The objective of ATFM is to ensure an optimum flow of air traffic.
ATFM should reduce delays to aircraft both in flight and on the ground and prevent system overload.
ATFM assists ATC in meeting its objectives and achieving the most efficient utilization of available airspace and airport capacity .
ATFM is to ensure that safety is not compromised by the development of unacceptable levels of traffic congestion and traffic is managed efficiently without unnecessary flow of restrictions being applied.
Communication
Air-Ground Communications
Most of the routine communications in the en-route phase of flight will be via data interchange.
Data transfers will also take place between automated airborne and ground systems without the need for manual intervention.
A special communication arrangement between controller and pilot is introduced that is named as Controller-Pilot Digital Link Communication abbreviated as CPDLC.
Controller Pilot Data Link Communications (CPDLC)
CPDLC will be part of the Aeronautical Data Link system and provide an additional digital communications channel to supplement the voice frequencies.
Multiple controllers will have the capability to send Data Link messages from any given sector to any or all Data Link equipped aircraft in that sector, and transmissions will take place simultaneously over multiple media.
A defined set of (pre-formatted) message elements is used, that correspond to existing phraseology employed by current ATC procedures.
A ‘free text’ capability is also provided to exchange information not conforming to defined formats.
Radio Links
Transmission of air-ground messages is carried out over one of the following radio links:
– Aeronautical Mobile Satellite Service (AMSS) – a new standard introduced in CNS/ATM
– VHF (analog) – traditional communication link– HF (analog) - traditional communication link– VHF digital link (VDL) – a new standard introduced in
CNS/ATM– SSR Mode-S data link – a new standard introduced in
CNS/ATM– HF data link – a new standard introduced in CNS/ATM
VHF Digital Link (VDL)
VHF Digital Link (VDL) is a mobile sub-network of the Aeronautical Telecommunication Network (ATN), operating in the aeronautical mobile VHF frequency band.
Modes of VDL
– VDL Mode - 2– VDL Mode - 4
HF Data Link System
The HFDL service allows aircraft to send and receive packet data via a network of HFDL ground stations.
HFDL can provide very significant improvements over current HF Voice Communications in terms of system availability, system capacity, ease of use, and information integrity.
Mode-S Data Link
Mode-S can be used to exchange longer and more varied data.
Mode-S transmissions between the station and the transponder use 56 or 112 bit formats called frames.
There are 24 formats. First five bits in each format define the Uplink Format No.
There are two types of Mode-S data link– Specific– Interoperable
Mode-S : Interoperable data link
The interoperable data link was designed to allow ground-to-aircraft exchanges using Mode S as a packet switching data transmission network.
The messages (data packets) transmitted are then cut into pieces and distributed around the data fields in the frames, which are sent from the station to the transponder (or vice-versa) where the data fields are extracted and reconstituted a little further on at the exit from the Mode S " world ", for routing to the addressee.
The interoperable services will enable the integration of Mode S sub-networks in the Aeronautical Telecommunication Network (ATN). It can, truly, be used as a data communication link.
Mode-S : Specific data link
The specific data link is more closely linked to the Mode S surveillance system. In particular there is a highly optimized "aircraft data collection" protocol using the COMM-B frames.
It is based on the following principle :
In the transponder, there is a series of 256 buffers of 56 bits each, in which information concerning the flight and aircraft status are stored and permanently refreshed. Each buffer, identified by an order number, contains data of a precise nature formatted according to a predetermined code.
Ground-Ground Communications
Means of Communications between and within ATS units:
• AFTN/AMHS, • Voice, or • ATS Inter-facility Data Communications (AIDC).
The use of AIDC significantly reduces the need for voice coordination.
The AIDC message sets and procedures are designed for use over any ground-to-ground circuit, including the AFTN and ATN.
Future CommunicationEnvironment
SSR mode S Air Traffic Services Unit
SSR mode SData link
VHF Data link
AeronauticalTelecommunicationNetwork
SatelliteData link
Satellite
SatelliteStation
Neighboring Air Traffic Services unit
HFData link
VHF Radio
HF Radio
Voice in non-routine and emergency situations
Voice
Navigation
Navigation
Improvements in navigation include the progressive introduction of area navigation (RNAV) capabilities along with the global navigation satellite system (GNSS). These systems provide for worldwide navigational coverage and are being used for worldwide en-route navigation and for non-precision approaches. With appropriate augmentation systems and related procedures, it is expected that these systems will also support most precision approaches.
Navigation satellites or Global Navigation Satellite System are alternative to NDB, VOR and ILS provided they meet the required standard.
GNSS (Global Navigation Satellite System)
Though GNSS is being used today for en-route navigation, but it requires augmentation systems to monitor signal reliability and enhance accuracy to make them suitable for Air Navigation Use.
GNSS, as specified in Annex 10, will provide a high-integrity, high-accuracy and all-weather worldwide navigation service.
The successful implementation of GNSS would enable aircraft to navigate in all types of airspace, in any part of the world, offering the possibility to dismantle some or all of their existing ground-based navigation infrastructure.
Augmentation Systems
• Ground based augmentation systems• Satellite based augmentation systems• Aircraft based augmentation systems
Ground based augmentation systems
• DGPS (USA)
• LAAS (Local Area Augmentation System)
• GRAS Ground-Based regional Augmentation System (Australia)
• European GBAS
• Korean GBAS
Satellite Based Augmentation Systems
• WAAS (Wide Area Augmentation System )
• EGNOS (European Geostationary Navigation Overlay Service)
• MSAS (Multi Satellite-based Augmentation System)
• GAGAN (GPS aided geo augmented navigation)
• Canada's CDGPS• K-SBAS (Korea)• SNAS (China)
Aircraft-Based Augmentation System
Aircraft-based augmentation system (ABAS - ICAO definition) augments and/or integrates the information obtained from the GNSS elements with other information available on board the aircraft.
GNSS +
Airborne Sensors
More accuratePositionInformation
ABAS
- RAIM (Receiver autonomous integrity monitoring
system)
- FDE (Fault Detection and Exclusion)- AAIM (Aircraft Autonomous Integrity Monitoring)
technique (GPS + other sensor)
Future Air Navigation Environment
Satellite Navigation Systems
Operational
• GPS• GLONASS
In development
• GALILEO• BeiDou-2 Compass• IRSS• QZSS
GPS (Global Positioning System)]
GPS was developed in 1973 by the United States Department of Defense for position fix coordination of the inertial navigation systems (INS) on board military aircraft and cruise missiles. It became fully operational in 1994.
In 1996, recognizing the importance of GPS to civilian users as well as military users, U.S. President issued a policy directive declaring GPS to be a dual-use system.
On May 2, 2000 "Selective Availability" was discontinued as a result of the 1996 executive order, allowing users to receive a non-degraded signal globally.
GLONASS
GLONASS is a Soviet space-based navigation system comparable to the US GPS system. Development of GLONASS began in the Soviet Union in 1976
Formally declared operational in December 1995 with constellation of 24 operational satellites.
Galileo
Galileo is a satellite navigation system currently being built by the European Union (EU) and European Space Agency (ESA).
Launched in 2011
Initial Operational Capability (IOC) to be completed around mid-decade.
Full completion of the 30 satellites Galileo system (27 operational + 3 active spares) is expected by 2019
BeiDou-2 or Compass
The BeiDou Navigation Satellite System or Compass) is a project by China.
It will be a global satellite navigation system consisting of 35 satellites
• Launched in 2007
• Planned to offer services to customers in the Asia-Pacific region by 2012 (with 10 satellites), and to global customers upon its completion in 2020.
IRSS
Indian Regional Navigational Satellite System (IRNSS) is an autonomous regional satellite navigation system being developed by the Indian Space Research Organization.
The first satellite of total seven satellites constellation is expected to be launched during 2012-2013. While the full constellation is planned to be realized around 2014
QZSS
Quasi-Zenith Satellite System (QZSS), is a proposed three-satellite regional time transfer system and Satellite Based Augmentation System for the GPS, that would be receivable within Japan.
QZSS can enhance GPS services in two ways: first, availability enhancement, whereby the availability of GPS signals is improved, second, performance enhancement whereby the accuracy and reliability of GPS derived navigation solutions is increased.
Surveillance
• Traditional SSR modes will continue to be used, along with the gradual introduction of Mode S in both terminal areas and high-density continental airspace. The major breakthrough, however, is with the implementation of automatic dependent surveillance (ADS).
Surveillance Types
• Independent Surveillance (IS)• Co-operative Independent Surveillance (CIS)• Automatic Dependent Surveillance (ADS)
Automatic Dependent Surveillance
• ADS-B (Automatic Dependent Surveillance-Broadcast)
• ADS-C (Automatic Dependent Surveillance-Contract)
ADS-A
ADS-Addressed (ADS-A) also known as ADS-Contract (ADS-C), is based on a negotiated one-to-one peer relationship between an aircraft providing ADS information and a ground facility requiring receipt of ADS messages.
For example, ADS-A reports are employed in the Future Air Navigation System (FANS) using the Aircraft Communication Addressing and Reporting System (ACARS) as the communication protocol. During flight over areas without radar coverage (e.g., oceanic and polar), reports are periodically sent by an aircraft to the controlling air traffic region
ADS-B
ADS-B periodically broadcasts information about each aircraft, such as identification, current position, altitude, and velocity, through an onboard transmitter.
ADS-B provides air traffic controllers with real-time position information that is, in most cases, more accurate than the information available with current radar-based systems.
ADS-B consists of two different services: ADS-B Out and ADS-B In.
ADS-B Principle of Operation
ADS-B: Physical Layer
Two link solutions are being used as the physical layer for relaying the ADS-B position reports.
• 1090 MHz Mode S Extended Squitter (ES)
• Universal Access Transceiver (UAT) 978 MHz
• VDL Mode-4
Traffic Information Service - Broadcast
TIS-B is a surveillance technique that broadcasts surveillance information from the ground for suitably equipped air or ground-based aircrafts, mobiles or objects of Interest .
TIS-B supplements ADS-B air-to-air services to provide complete situational awareness in the cockpit of all traffic known to the ATC system.
Future SurveillanceEnvironment GNSS
Secondary surveillance radar mode S
Air Traffic Control
SSR mode SData linkVHF or HF
Data link
ADS
RadarSurveillance
AeronauticalTelecommunicationNetwork
VHF or HF Radio
SatelliteData link
CommunicationSatellite
SatelliteStation
Air TrafficControl
Airborne Systems
• Cockpit Display of Traffic Information (CDTI)
• FMCS (Flight Management Computer System)
• Multi-Mode Receiver (MMR)
• Collision Avoidance Systems: ACAS (Airborne Collision Avoidance System) TCAS (Traffic Alert and Collision Avoidance
System)
• Automatic Dependant Surveillance – In & Out• Airline Operational Control Datalink• Air Traffic Control (ATC) Datalink• GNSS or Global Positioning System Receiver
Aeronautical Telecommunication
Network
ATN (Aeronautical Telecommunication Network)
ATN allows ground, air-ground and avionics data sub-networks to inter-operate for the specified aeronautical applications.
All the afore-mentioned data links are ATN-compatible and therefore constitute ATN sub-networks.
In ATN environment, sub-networks are connected to other sub-networks through ATN routers, which select the best route for transmission of each data message. As such, the choice of the air-ground data link is often transparent to the end-user.
CONCLUSION
Communication
a) Voice Air-Ground Communications: VHF, UHF, HF and SATVOICE (SATVOICE is a satellite telephone system that is available on suitably equipped aircraft through the Inmarsat Geostationary Satellite Network)
b) Data Link Air-Ground Communications: Controller Pilot Data Link Communications (CPDLC) application via data link utilising Satellite, VDL, HFDL and Mode-S sub networks
c) ATS Ground-Ground Communications: Voice communications; ATS Interfacility Data Communications (AIDC); AMHS and AFTN.
d) DSP (Data Link Service Providers} Internetworking.
e) Aeronautical Telecommunication Network
Navigation
The major technological changes in navigation are the adoption of Global Navigation Satellite Systems (GNSS).
The level of aircraft navigation capability required for particular operations is expressed by Performance Based Navigation (PBN) criteria.
Surveillance
Surveillance information will be obtained by – Automatic Dependent Surveillance (ADS)– SSR Mode – S
Traditional surveillance means such as Radar (both Primary and Mode A/C) will also be used.
Traffic information will be broadcasted from ground ATS centers via TIS-B.
Application of IT in CNS/ATM
Information Technology deals matters concerned with computer science and technology, design, development, installation and implementation of information systems and applications
Because of advantages such as Reliability, Flexibility, Multi Facility Integration, Expanded Operation, User convenience, Security (of information) IT is involved in all the three components of CNS/ATM; that is Communication, Navigation and Surveillance.
IT makes the future ATC/ATM systems and Voice/Data communication networks work efficiently at enormously high speeds.
Future Environment as foreseen by AIRBUS industriesCNS/ATMCNS/ATM overviewoverview
CommunicationSatellites (Satcom)
Space
Air
Ground
Ground Network for
Data Communications
SatcomGround-based radios
(VHF & HF) Transponder
NavigationSatellites (GNSS)
Airline Host Information Service ATC Center
DifferentialGNSS station
What’s the Future ?
FREE FLIGHT
Thank You
Questions ?