GNSS IN COMMERCIAL AVIATION: IMPACTS, OPPORTUNITIES AND CHALLENGES

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With the increasing demand for air-travel, the commercial aviation industry has been experiencing rapid growth all over the world, with increasing number of air routes and aircraft, owing to the entry of airlines and expansion of existing airlines. This rapid growth has simultaneously witnessed various challenges including financial, regulatory and operational challenges to name a few. The operational challenges seem more significant from the growth standpoint as these challenges obstruct airlines and regulatory bodies from utilizing the available opportunities to the full. With the increase in the number of aircraft, airspace management has become more challenging than it was before. Safety and accessibility are the main elements of the operational challenge that airlines, airports and regulatory bodies face. With the advancement of technology, there have been simultaneous innovations into instrument-guided airspace management procedures. These technology implementations often take the form of Augmentation Systems, with their infrastructure being ground based for the most part. The space programs have contributed multiple constellations of navigation satellites, which have added to the efficiency and accuracy of these augmentation systems that are used to guide aircraft. This inclusion of the space segment into the otherwise ground-based augmentation systems has made the concept of aircraft guidance and tracking, a more versatile and reliable practice that is being used to manage airspace around the world. It would be beneficial at this point to look at the possible applications of satellites i.e., Global Navigation Satellites Systems (GNSS) in the commercial aviation industry, with a specialized interest into business opportunities that may emerge as the result of this technological advancement. This research, in its own limits, attempts to look into the aspects of growth of commercial aviation, the resultant airspace management requirements and the subsequent opportunities that may involve the application of GNSS in commercial aviation. Click here to download the pdf version of this post.

Objectives

The primary objective of this post would be to identify the future trends of commercial aviation that may demand the implementation of GNSS-based augmentation systems. The secondary objective would be to identify possible aspects of GNSS-based systems that may satisfy the future airspace management requirements of the commercial aviation. The discussion objective would be to interpret the relation between the primary data and secondary data and arrive at a brief description of possible impacts, opportunities and challenges to be faced while attempting to implement GNSS-based systems in commercial aviation.

Methodology

This research would tend to be interpretative in nature and therefore it shall require initial inputs from individuals with professional experience in the aviation sector regarding the impact of implementing GNSS in commercial aviation and growth of commercial aviation in general. These inputs would serve as the primary data, based on which internet research shall be carried out to obtain published research work from the private and government sectors that may serve as secondary data.

The data collected shall be analyzed to capture important aspects of commercial aviation that may require the application of GNSS and the subsequent impact of GNSS on it. Interpretations shall be made based on the facts obtained from the primary and secondary data and it shall be used in further discussion.

Primary data was collected through telephone interviews. Secondary data was collected from various online resources based on the interpretations of primary data.

Primary Data

Interviews

Interview-I:

Interviewee: Certified Flight Dispatcher (Past)

Trained on: Boeing 737 (Location: UAE)

Interview Summary:

He briefly explained how flight operations are managed by flight dispatchers in coordination with various departments and air-traffic controller. He stressed the importance of scheduling and filing of flight plan and the important aspects of the flight plan that directly impact the airline operations. When asked regarding GNSS applications in commercial aviation, he responded with positive comments for GNSS applications, mentioning the systemization of the process and how drafting flight plans would be simplified owing to standardized cruise and approach routes that are implemented as a result of implementing GNSS. He also mentioned about the segmented airspace controlled by each airport and how the segmentation impacts the airport operations.

Interview-II:

Interviewee: Aviation Business Analyst

Experienced in: Forecasting (Aircraft Manufacturing & Sales)

Interview Summary:

He briefly explained about the trend in aircraft sales over the past few years where the delivery backlogs have steadily increased, indicating the expected addition of aircrafts to various fleets in the coming years. He mentioned that, as a precautionary measure, buyers have chosen their delivery times much further into the future, expecting the economic climate to recover before they receive their ordered aircrafts. He also mentioned that, in the coming years, more aircrafts are expected to be added to the current fleets, influencing a denser air traffic pattern. While talking about air traffic in commercial aviation, he mentioned that in the past few years there have been many mergers among airlines resulting in increased fleet size. He mentioned that if the airlines which bought the aircrafts used them to increase number of flights in existing routes, the corresponding airports would begin to face denser flight traffic.

Secondary Data

Published Research Work

Based on the interpretations of the primary data collected through interviews, the subsequent internet research was done and published research work from the academic, government and industrial sectors that are available in the public domain were downloaded. The documents were read and specific information and ideas pertaining to the topic at hand and those corroborating the ideas captured in the interviews were picked, studied and the subsequent interpretation of the ideas were used as the basis for the discussion presented below.

Growth in Commercial Aviation

As per the estimates of Global Traffic Forecast initiated by Airports Council International for the period of 2006-2025, the world passenger volumes is expected to increase by 4% annually and the freight volume is expected to increase with a growth rate of 5.4%. These estimates indicate the need for more air travel which may be satisfied by increase in the number of flights and addition of aircrafts. The commercial aviation sector, that tends to meet the major portion of the demands of the increasing passenger and freight traffic, is set to grow over time, making airports busy and airspace management more complicated. This increase in aircraft movement would result in the increase in the need for supporting infrastructure in the forms of newer airports, additional air routes and improved air traffic control systems. 

The Global Market Forecast for the period 2012-2031, done by Airbus, indicates that the air traffic between advanced and emerging air transport markets is expected to increase at an average annual rate of 5.1%. The forecast also indicates that the number of passenger and freight aircraft fleets, by 2013, is expected to have increased by 109% and 82% respectively.

This growing number of aircrafts would require an increased availability of aviation infrastructure, mainly airports and air traffic control systems. The primary demand would therefore be for availability of space on land and in air, to meet the operational demands of safety and accessibility, which may translate into more and larger airports with more efficient air space management procedures. The improvement if airspace management procedures would help make use of the available infrastructure to the full, by contributing to safety and accessibility.

This evolution of airspace management has so far been predominantly dependent on aircraft/ground based augmentation systems and with the implementation of GNSS, the satellite-based augmentation systems have emerged with increased capabilities and efficiencies. The future of better airspace management would however require a combined implementation of ground-based and satellite-based augmentation systems, facilitating the evolution of more versatile and adaptive augmentation systems that may include ground and space segments working together to achieve the objectives of efficient airspace management. The cost constraints of implementing GNSS-based guidance system may be considerably lowered by using the available ground-based augmentation systems. It however is an obvious requirement that the ground-bases augmentation system be compatible with GNSS and related systems.

Need for Improved Airspace Management

With more aircrafts and more flights, the air traffic gets denser requiring airports to implement GNSS-based airspace management systems and procedures in order to ensure aircraft safety and airport accessibility. Making airports accessible to more aircrafts means, more air traffic near airports which in turn indicates increased risk of accidents. As per the Statistical Summary of Commercial Jet Airplane Accidents (1959-2008) released by Boeing indicate that 36% of the accidents take place during the final approach/landing phase and 20% of accidents take place during take-off/initial climb phase of flight. Fig.1 given below indicates various phases of flight and the percentage of accidents/fatalities that occurred during 1959-2008. 

Fig 1. Accidents/Fatalities by Phase of Flight

(Source: Statistical Summary of Commercial Jet Airplane Accidents, 1959 - 2008, Boeing)

This translates to the fact that aircrafts are more vulnerable to accidents in the controlled airspace around the airports than anywhere else. Therefore, the airspace management systems and procedures need to address the need for increased airport accessibility and risk of accidents. 

The major airspace management requirements to be satisfied are:

·   -      Optimization of aircraft holding areas in air

·   -      Avoiding collision

·   -     Increased airport accessibility 

These major requirements can be met with the following elements of airspace management (including but not limited to):

·  -       Improved instrument flight procedures

·  -       Predictable/repeatable flight trajectories

·  -       Closely spaced routes

·  -       Implementation of progressive airspace management regulations

The application of GNSS would contribute to the design and implementation of efficient satellite-based augmentation systems and procedures that may include the following aspects:

·  -       Improved flight path monitoring tools

·  -      Increased systemization of navigational control procedures

·  -     Increased controller productivity

·  -    Increased system adaptability to evolving airspace user requirements

·  -   Increase in controlled airspace capacity

GNSS in Commercial Aviation

There are multiple GNSS in operation and many global and regional navigational satellite systems are expected to be in operation in future. Application of GNSS requires accessibility to the navigational satellite system and corresponding augmentation systems that accommodate the space segments in addition to the ground based augmentation infrastructure. The civil aviation regulations also play an important role in the design and implementation of such GNSS based guidance systems. Fig. 2 given below shows a schematic representation of a typical GNSS based airport guidance system:

Fig 2 Typical GNSS Based Airport Guidance System

(Source: US Patent No. US 6,182,005 B1 dated Jan 30, 2001, Pilley et al)

As described in Fig.2, the GNSS based guidance system would be composed of a framework of ground and space segments, mobilized by systemized detection, processing and display of vehicle positioning data, relying on standardized databases that contain all the necessary data. This also means that such a GNSS-based system would implement a high level of systemization, reducing the chances of human error that may cause anomalies in air traffic management processes.

Impact of GNSS in Commercial Aviation

Satellite-based augmentation systems add to the operational efficiency and accuracy in a multitude of operations including:

·       -   Departure Operations

§  Take-Off

§  Initial Climb

·       -   Arrival Operations

§  Approach

§  Landing

·       -  En-route Operations

·        -  Terminal & Surface Operations

·        -  Collision Detection & Alerting (based on Trajectory Prediction)

This implementation of GNSS-based systems would result in the upgradation of conventional instrument-controlled flight procedures/systems or their subsequent decommissioning, owing to the entry of the more precise satellite-based augmentation systems. The implementation of GNSS-based systems would however be transitional in nature, spread over an extended period of time, owing to the installation requirements in terms of ground-based and on-board equipment and subsequent air-traffic procedural amendments as regulated by the civil aviation authorities of the region. This is one reason why any ground-based augmentation system needs to be designed so as to allow future GNSS compatibility.

From the operational standpoint, air traffic controllers and pilots would have enhanced navigational data with both ground-based and on-board graphic displays apart from the simplification of instrument-controlled flight procedures which may reduce pilot fatigue and enhance operational easiness. The airports would be able to handle more air traffic efficiently and the operators would have reduced burden of safety with respect to flight operations. There will be an element of “situational awareness” among the air traffic controllers and pilots enabling easy identification of conflict scenarios.

With the implementation of standardized airspace management procedures, airports in their own region would have enhanced interoperability, simplifying operations in the particular region. There will be fewer major operational discrepancies and corresponding transition methods in place for uninterrupted flight services between airports from different regions (with contradicting aviation regulations). 

Europe and the US has so far been the major user of GNSS-based guidance systems in commercial aviation. The Russian, Chinese navigational satellite systems also provide similar navigational opportunities to their respective commercial aviation sectors. The availability of an indigenously developed navigational satellite system would considerable reduce the cost of implementing such systems in the commercial aviation sectors.

The concept of GNSS-based aircraft/airport guidance is very subjective and therefore may vary in terms of applied methods and processes from place to place, owing to the geographic, regulatory, air-traffic and operational constraints. The GNSS-based guidance systems, though following an overall system design pattern, would tend to vary from region to region in terms of their size, operational functions and range. Therefore implementing GNSS-based guidance system for developing air transport markets may be different as compared to that for an already existing air transport market.

Opportunities To Be Explored

 

Navigation Infrastructure:

From the emerging navigational technologies perspective, the primary requirement for design and implementation of a GNSS-based guidance system would be the assessment of the navigational needs and existing navigational infrastructure. The system in its course of design and implementation would require continuous monitoring and assessment. Therefore, opportunities for Navigational Infrastructure Assessment would be an important domain that would require players to meet the demand for assessment of navigational needs and infrastructure in the implementation of GNSS-based guidance systems. These opportunities would create requirements of GNSS-compatible navigational equipment and implementation/maintenance services in the short and long-term. Depending on regional civil aviation regulations, the GNSS-compatible avionics may need to match specific regulatory and user requirements. The design and development of such avionics is another field of opportunity that would be a result of implementing GNSS-based systems in commercial aviation.

Navigation Specification:

Development and implementation of improved instrument-controlled flight procedures is another domain of importance which requires multiple players to work in collaboration with regional civil aviation regulatory bodies. For the implementation of any satellite-guided system, there would be corresponding changes to conventional air traffic management practices. Private sector businesses that specialize in technology research and consulting would have ample opportunities to work with airport administrations to implement their choice of GNSS-based guidance systems and procedures. There would be demand for airspace planning and trajectory design that would need to be addressed.

Testing, Training & Certification

With the implementation of GNSS-based augmentation systems, airport operators and airline operators would be required to install necessary navigational equipment, on ground and on board. The testing, analysis and certification of such instruments so as to match the regulatory requirements of the region would be an operational burden that operators would be willing to outsource to private players. Also training the process owners including the controllers and pilots with the new systems and their functionality would be an operational exercise that operators would be required to do which again can be outsourced to private organizations that specialize in imparting such technology training programs and related services.

Challenges for GNSS Applications in Commercial Aviation

The application of GNSS in commercial aviation, in spite of its technological superiority and adaptability, would face the following major challenges (including but not limited to):

Cost:

Additional installation of GNSS-compatible equipment in the ground stations and aircrafts and their subsequent certification before use imposes a substantial cost on the airline operators and airport authorities. The civil aviation regulatory bodies of each region need to restructure their regulations so as to accommodate implementation of such systems so that airline operators are motivated by a substantial benefit in exchange for volunteering to the transition.

Back-Up:

A progressive decommissioning of augmentation systems that are replaced by GNSS-based systems would impose the risk of not having a viable back-up as a deterrent to the technological transition. Therefore the basic infrastructure for the existing ground-based augmentation systems need to be kept alive and synchronized with the satellite-based augmentation system so as to serve as a back-up in case of a system failure in the event of deliberate jamming or solar flares. This would impose a requirement for ground-based augmentation system infrastructure to be GNSS-compatible so as to allow future transition.

Time:

Flight trials analysis involving GNSS-based approaches conducted through a collaborated effort of Imperial College of London and University of Leeds, indicates that a large portion of the pilots were confused with the system installation status and the most safety relevant issue was pilot confusion over range information displayed that complicated the calculation of vertical descent profile. This is an indicator that an implementation of a newer navigational system and corresponding procedures would require a formal training program so that the process owners (pilots and controllers) get oriented to the new system features and improved procedural formalities. Any abnormalities identified during the training period would require system/sub-system level changes. There will be a significant time and resource cost to be met while attempting to train the process owners with newer technologies and optimizing the installed infrastructure/equipment as per the feedback received during the operational testing. Any time delay in the implementation to the effective-in-operation stage would mean that the investment would take longer time to respond with a return, which may impose financial constraints that may be demotivating to the investors.

Conclusion

The application of GNSS in commercial aviation, in terms of technology is a valuable advancement that caters to a diverse set of demands that may arise due to the expansion of the commercial aviation market. Although developed air travel markets have implemented GNSS in their commercial aviation sectors, the implementation has so far required intensive regulatory, infrastructural and technological transformations and is bound to evolve further with standardized regional airspace management concepts. The developing air travel markets would have an additional burden of infrastructural costs as they are yet to become entirely compatible to GNSS-based systems. With civil aviation authorities coming forward with appropriate regulatory changes combined with a collaborated effort from airport/airline operators and technology partners, application of GNSS in commercial aviation would turn out to be beneficial to all the entities constituting commercial aviation. GNSS would increase the safety of aircrafts, especially while operating the controlled airspace of an airport, adding to the operational ease and accessibility to airports, positively impacting the fast growing commercial aviation sector. There is a cost constraint that may hinder the smooth transition into GNSS-based technology and a financial analysis of such implementation, on a case-by-case basis, elaborating the cost versus benefit aspects of implementing GNSS in aircraft/airport guidance would help operators in deciding on transitioning to the new technologies.

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References

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2.       Luis Chocano. GNSS-EGNOS Approaches to European Airports. United Nations International Meeting on the Applications of Global Navigation Satellite Systems, Dec, 2011, Vienna.

3.       Leo Eldredge. Aviation Considerations for Multi-Constellation GNSS. GNSS Group, Federal Aviation Administration, Dec, 2008.

4.       Dr. W Ochieng, C Milner, M Daly. RNAV (GNSS) Non-Precision Approach – Flight Trials Analysis Report. Civil Aviation Authority, Sep, 2007, United Kingdom.

5.       Civil Aviation Authority. Future Airspace Strategy for the United Kingdom 2011 to 2030. June, 2011, United Kingdom.

6.       SESAR Consortium. The ATM Target Concept D3. Sep, 2007.

7.       Harold Robert Pilley, Lois V. Pilley. AIRPORT GUIDANCE AND SAFETY SYSTEM INCORPORATING NAVIGATION AND CONTROL USING GNSS COMPATIBLE METHODS. Patent No: US 6,182,005 B1, Jan, 2001, United States of America.

8.       DKMA. GLOBAL AIR TRAFFIC FORECAST 2006-2065. Airports Council International. 2007.

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11.   Ajay Prasad Committee. Future Air Navigation Master Plan. Ministry of Civil Aviation, Mar, 2007, India.

12.   Boeing. Current Market Outlook 2013 – 2032. 2013, United States of America.

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Regards,