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Opportunities in aviation and GPS

Sanjeev Goel
Sanjeev Goel
Centre For Technology Training
218 Agcr Enclave
Vikas Marg Extension
Delhi 110092, India
[email protected]
[email protected]

The air transport industry has developed a new operational concept for the Air Traffic Management (ATM) system, which involves dramatic changes to the airplanes, infrastructure, and ground systems. The current ATM system (based on ground navigational aids, radar, and voice communications) will be unable to cope with expected air traffic growth.

The industry has responded by developing an operational concept known as the Future Air Navigation System (FANS) which relies on space based navigation and communication to provide the improvements needed in Communication, Navigation, and Surveillance (CNS) to efficiently cope with future traffic levels and to provide a level of efficiency to current operations.

The FANS concept broke new technical ground as it required industry to consider ATM as a system with ground components, space components, and airborne components. The International Civil Aviation Organization (ICAO) FANS committee also committed to certain technical solutions for improvements to CNS such as Aeronautical Telecommunications Network (ATN), GPS navigation, and satellite communications. The Air Traffic Management ( ATM ) system must not only be considered as a system; it must also be considered as a business

The evolving Free Flight or Flight2000 is an innovative concept designed to enhance the safety and efficiency of the Airspaces. The concept moves the airspace concept from a centralized command-and-control system between pilots and air traffic controllers to a distributed system that allows pilots, whenever practical, to choose their own route and file a flight plan that follows the most efficient and economical route.

The providers of air traffic control services, the users of these services, and financing organizations all need to be advised of the financial implications, and convinced of the economic viability, of the new CNS/ATM systems. In addition to the assessment of over-all viability, it is important to determine the separate impacts on administrations responsible for providing the services, and on airlines and other aircraft operators who use the services


The Revolutionary Evolution
Imagine an airspace environment in which airlines and other airspace users have the freedom to select preferred flight paths in real time, with virtually no restrictions. While this degree of freedom is not available as yet, it is a goal air traffic controllers the world over attempt to achieve every day through their efforts to accommodate flights with the most direct and efficient routes possible. It is a goal second only to the prevention of collisions – that is inherent in the air traffic control (ATC) system. Constraints caused by permanent airspace reservations for national purposes and technical limitations in the ATC system have so far rendered this goal elusive.

In 1983 ICAO chartered the Special Committee on the Future Air Navigation System (FANS) to study the current air traffic infrastructure and recommend changes to support the anticipated growth in air traffic over the next 25 years.

Constraints with the Present Aviation Infrastructure
The present air navigation system can not support the predicted air traffic growth in the next two or three decades in terms of capacity, efficiency and levels of safety. The FANS committee identified the following limitations in the present system:

  • Limitations of line-of-sight systems in terms of propagation distance, accuracy, and reliability;
  • Difficulty of implementing and operating systems in a consistent manner around the world;
  • Limitations of voice communications and
    Lack of digital air-ground data interchange systems to support automation in the airplanes and on the ground.

Key Elements of the Proposed CNS ATM Infrastructure

Transition to digital air/ground communications from today’s analog radios

Transition to a Global Positioning System (GPS)-based navigation and landing and subsequent decommissioning of ground-based navaids and precision approach aids.

Transition from ground-based surveillance to dependent cooperative surveillance of GPS-derived position

Air Traffic Management
Transition from existing en route and traffic management to common Air Traffic Management (ATM) platforms, consistent user interfaces, and common of support software.

The other principal transitions are:

  • Transition of existing terminal automation infrastructure to new systems based on commercially available hardware and software.
  • Implementation of new capabilities such as conflict probe, conflict resolution, and collaborative decision making.
  • Transition to integrated displays and information processing in air traffic control towers.
  • Replacement of existing oceanic automation / displays and introduction of data link to allow reduced separation standards in the oceanic domain.
  • Installation of flight service automation to enable pilots to plan and file flight plans without reliance on flight service specialists.

These new systems will support Free Flight operational capabilities at a significantly lower cost than operating a ground-based CNS infrastructure.

The transition to CNS/ATM systems will be one of the largest undertakings ever carried out by the aviation community, not only because of the immense scale of the change but also because the transition will fundamentally affect how aviation administrations provide air traffic services. A broad indication of how the transition might proceed is as follows:

Continuing developments, trials and pre-operational demonstrations. Present-2000. Gradual implementation and use of various elements of the system. Some aircraft and administrations will use the CNS/ ATM systems with backup from the terrestrial systems.

Full CNS/ATM services available in parallel with existing systems so that appropriately equipped aircraft can have maximum operating benefits from the CNS/ATM systems.

The international terrestrial system not required for the CNS/ATM systems progressively dismantled.

The CNS/ATM systems are the sole systems for international use. In any such transition timetable, there will be a period when the CNS/ATM systems and the existing terrestrial systems are operating in parallel. While this period allows for aircraft operators to change their equipment, and for service providers to phase out those ground facilities which will no longer be required, maintaining two systems is very costly. The costs associated with the transition are therefore an important component of the economic assessment of the CNS ATM systems.
Table: 1 CNS Systems Evolution

Airspace Function Current system Future System
Oceanic continental En-route airspace with high / low-density traffic Navigation



OMEGA/LORAN-C NDB VOR/DME Barometric altimetry INS/IRS

VHF voice
VF voice

Primary radar/SSRVoice position reportsOMEGA/LORAN-CNDB

RNAV/RNPGNSSBarometric altimetryGNSS altitudeINS/IRS

VHF voice/ data AMSS data/voice HF voice ; North and South poles only



Continental airspace with high-density traffic Navigation




Barometric altimetry


Primary radar
SSR Mode A/C

Barometric altimetry GNSS altitude


VHF voice/data AMSS data/voice SSR Mode S data link

SSR[Mode A/C orMode S]

Terminal areas with high-density Navigation



NDB VOR/DME ILS Barometric altimetry INS/IRS


Primary radar
SSR Mode a/c

Barometric altimetry
VHF voice/data
SSR Mode S data link
AMSS data /voice

SSR [Mode A/C or Mode S] ADS

Evolving Ground Infrastructure
The Aeronautical Telecommunication Network (ATN) is being defined within the International Civil Aviation Organization (ICAO) as a digital data communications network for the aeronautical community. The ATN is a key component of the Future Air Navigation System (FANS) which includes enhanced communications, navigation, and surveillance capabilities necessary to improve the efficiency of the global air traffic management system.

The ATN will allow the interconnection of a diverse collection of air-to- ground and ground-to-ground communications systems to provide global information transfer among computers used for air traffic management, airline operations, general flight information services (such as weather), and passenger services. Building the ATN requires special communications components, called ATN routers, both in the aircraft and on the ground.

These routers will interconnect the various communications systems and ensure that communications paths between all users, including aircraft in flight, are available throughout the network.

Implementation of FANS and the ATN will result in major benefits to both the public and private sectors. Benefits to civil aviation authorities and airspace users will include reduced costs for communications services through increased competition and the use of shared networks, and increased communications reliability and capacity.

The major benefits of FANS will come from the more efficient use of the airspace allowed by improved automation and communications. In 1994, the FAA outlined the incremental changes in air traffic control procedures for aircraft that will be possible with FANS equipment, including ATN, operating over the oceans. Those changes included reduced separation standards, reduced mandatory fuel reserves, and more efficient routes for equipped aircraft.

Efficiency Benefits due to CNS ATM

  • The improved navigation, communications and surveillance brought about by implementation of CNS/ATM will allow more direct routing of aircraft, which will generate savings in fuel cost and other aircraft operating costs. The amount of these savings will depend on the reduction in the number of aircraft-hours flown in the airspace as a result of CNS/ ATM and on aircraft operating costs per hour.
  • Communications and navigation improvements, which produce more direct flight paths and less delay from airspace congestion, will reduce the passenger travel time for a given journey. If passengers value these time savings, they represent an additional benefit.
  • FANS will revolutionize the economics of airline operations whilst offering enormous benefits to air traffic control agencies, as well as to national economies.
  • Through FANS implementation, the rising demand for air travel will be met and at a higher level of safety than possible today.
  • Congestion and delays should decrease, with airport and airspace capacity being used as efficiently as possible.
  • Airlines will be able to fly more efficient routes, thus reducing their fuel and other operating costs.
  • Air navigation service providers will be able to reduce the number of expensive ground based navigation aids, realizing savings. Improved air transport efficiencies will make a positive contribution to economies; opportunities for travel, tourism and cargo shipment will increase, even as airlines reduce the environmental impact of each flight.

Table 2 : Project life cycle

Benefit mechanisms involve capacity and/or efficiency enhancements by phase of operation. The phases of operation used are:

  • Airport surface region
  • Final approach/Initial departure region
  • Approach/Departure transition region
  • Procedurally defined climb / descent (SIDS / STARS) region
  • En-route / Oceanic region.

The throughput in all of these regions determines the capacity and efficiency of the total air traffic management system.

…And the Challenges

  • Airlines and Air Traffic Management agencies will both be hesitant to invest in the necessary equipment until they are convinced that their costs can be recovered. Who will have the vision to make the first move?
  • To achieve the full economic benefits of FANS, unprecedented levels of international cooperation between governments, airlines, suppliers and ATC agencies will be needed to ensure the transition to FANS is both global and rapid, smooth and well coordinated. Common standards must be established and kept.
  • Bold thinking is needed to overcome concerns about national control over airspace. Creative new approaches to the regional management of air traffic will maximize the benefits of FANS.
  • New forms of financing will have to be found to help those developing countries and airlines that are unable to afford the necessary investments.

Economic Appraisal
Investments in the aviation infrastructure are required continuously in order to maintain safety and reliability, improve the quality of service and match system capacity with the expected traffic growth.

The decision-maker, who is responsible for sanctioning future projects, will require a clear understanding of the advantages and disadvantages of the proposals.

Cost – Benefit Analysis (CBA) is widely accepted as a vital support tool for economic analysis in Air Traffic Management (ATM). To be most effective CBA should be invoked as early as possible in the project life cycle ( See Table 2 ). Project sponsors will need to know at an early stage (before detailed requirements are drawn up):

  • what type of benefits their project is likely to bring;
  • how much (approximately) these benefits will be worth in economic terms;
  • who will receive the benefits (the beneficiaries);
  • what the associated costs are likely to be.

Table 3 : Outline of a typical CBA
An outline of a typical CBA is shown in Table 3.Cost types

In general project costs should be categorised under three headings:

  • investment costs, associated with the acquisition of equipment, property, services, operating start-up costs, and other one-off expenditure for the project;
  • operating costs comprising: staff – internal/external, civil/ military; operations – maintenance & repair, materials, supplies, utilities and other services; overhead -administration, personnel, training;
  • transition costs occur where it is necessary to maintain parts of the current system during the transition period to a new system.
  • The major cost could fall into the following: ( not exhaustive )

Note: 1. Blocks 3,8 and 13 are no longer
2. The flows from the CNS/ATM System to the Search and Rescue Organisation, to Accident/Incident investigation Authorities, as described in the figure – final and Context Model
(in Chapter 3, Volume 1), are not explicitly indicated
3. The flow from Airport Operators to the CNS/ATM System, as described in the figure – final
Scope and Context Model (in Chapter 3, Volume 1), is not

ATC Service Providers

  • CNS ATM equipment investment
  • Investment in present technology
  • Maintenance and Operational
  • Purchases of intermediate services
  • Retraining
  • Decommissioning of existing systems Staff redeployment

Aircraft Operators

  • CNS ATM equipment investment
  • Investment in present technology
  • Maintenance
  • Purchases of intermediate services
  • Retraining

The potential benefits of a project should be identified and listed:

  • ATM service provider and Airline cost savings
  • Airspace capacity benefits
  • Reduction in delays
  • System reliability benefits
  • Safety benefits
  • Upgradability
  • Contingency
  • International commitments;
  • Environmental benefits.

The main Functional Blocks of the CNS/ATM system are those identified below:

  • Airborne CNS/ ATM Component;
  • Aeronautical Environment Processing;
  • Air Traffic Flow Management;
  • Surveillance;
  • Flight Data Processing;
  • ATC Tools;
  • Communications;
  • Navigation;
  • CNS/ATM Support;
  • Airspace Management.

Data link will provide three major evolutionary capabilities

  • Services that support communications between pilots and controllers
  • Ground-based services that provide relevant information to pilots
  • Decision support services that support coordi-nation among flight decks, airline operations centers (AOCs), and air traffic management services for efficient flight management.

The data link section discusses services in the fol-lowing order

  • Controller-Pilot Communications and Air Traffic Services:
  • Tower Data Link Services (TDLS)
  • Data Delivery of Taxi Clearance (DDTC)
  • Controller-Pilot Data Link Communica-tions (CPDLC)
  • Oceanic Two-Way Data Link Communica-tions (TWDL) Services

Flight Information Services:

  • Flight Information Service (FIS)
  • Meteorological Data Collection and Reporting System (MDCRS)
  • Terminal Weather Information for Pilots (TWIP)
    • Traffic Information Service (TIS)
    • Decision Support System (DSS) Services.

Air / Ground Data Communications Services

  • Controller Pilot Data Link Communications (CPDLC) : a means of communication between Controller and Aircrew, using data link for Air Traffic Control communications.
  • Automated Downlink of Airborne Parameters (ADAP) : a means of providing aircraft status and Aircrew preferences information to Controllers and ground systems using air/ ground data communications.
  • Data Link Flight Information Services (D-FIS) : a means of providing flight information (e.g. ATIS and meteorological information) to Aircrew using air/ground data communications.

Accommodate diverse user telecommunications requirements.

Migrate from dedicated connectivity to bandwidth on demand.

Integrate voice, data, and video communications within the network.

Consolidate operational and administrative networks.

Centralize telecommunications network management.

Reduce operational and life cycle cost through more efficient system design.

Also Known as “Space based Augmentation System”( SBAS )

Also Known as Ground based Augmentation System ( GBAS )

Proposed Surveillance System Architecture

ATM Concept Components
Air Traffic Management

Project cost Data
The cost data are provided and are classified as follows:

  • Investment Costs
    • R&D costs
    • Procurement costs
    • Integration costs
    • Installation costs
    • Testing and Validation costs
    • Commissioning/Certification costs
  • Transition Costs – Costs incurred due to the partial maintenance of the current system during transition to the new system.
  • Operating Costs
    • Staff costs (internal/external, civil/military)
    • Operations (maintenance, repair, materials, suppliers, utilities, other services)
    • Overhead (administration, personnel, training, pensions, repayment on loans)

The investment and transition costs are one time only costs and hence are classified as “non-recurring”, whereas the operating costs are incurred each year and are classified as “recurring”.

Thank you and have a nice flight
Worldwide Document References

  • National Airspace Architecture ( NAS ) of US
  • EuroControl , ICAO, IATA, FAA Updates.