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International Civil Aviation Organization
Working Paper / ACP-WGF27/WP-22
2012-09-12

AERONAUTICAL COMMUNICATIONS PANEL (ACP)

TWENTY SEVENTH MEETING OF WORKING GROUP F

Montreal, Canada 17 – 26 September 2012

Agenda Item 5: / Interference from non-aeronautical sources

Radionavigation-Satellite Interference

(Presented by John Mettrop)

SUMMARY
This paper looks at the radio regulatory status of the radionavigation-satellite service, the range of applications provided and the implication for aviation.

1.  INTRODUCTION

1.1  GPS and other radionavigation-satellite systems such as GLONASS, GALILEO, COMPASS and IRNSS is a space based navigation system that can be used to provide location and timing information anywhere in the world.

1.2  Development of GPS was initiated in 1973 with the intention to overcome some of the shortcomings of existing terrestrial navigation systems, with a constellation of 24 satellites, as originally envisaged, being completed in 1994.

1.3  Whilst these systems were originally developed for military purposes, their usefulness to the civil community was recognised and in 2000 the USA turned off selective availability thus improving the accuracy for cvil systems. A similar step was taken by the Russian Federation in 2007 with respect to GLONASS while the other systems have been designed from concept to offer a civil service.

1.4  For aviation these radionavigation-satellite systems provide a useful resource which is currently being used in the provision of precision based navigation systems as well as being considered for use in communication and surveillance systems.

2.  discussion

2.1  Whilst radionavigation-satellite systems, especially GPS, are a useful resource for the civil community including aviation as well as the military for whom they were originally designed, they have been a victim of their own success.

2.2  As the range of applications has increased so the number of people who wish to either modify or deny a service to either themselves or others has increased. Intentional interference has therefore become an ever increasing issue with jammers/spoofing being produced for both the military and civil markets.

2.3  The incident highlighted in the recent State Letter AN13/4.5-12/50 near the border between North and South Korea and the alleged spoofing of a US military drone are two military examples but there are numerous examples within the civil area, including a number of incidents at Blackpool airport in the UK.

2.4  The Radionavigation-satellite service is defined under RR article 1.43 as “A radiodetermination-satellite service used for the purpose of radionavigation”. Since a radionavigation-satellite service is for the purpose of radionavigation, RR Article 4.10 is applicable and it is regarded as a safety service. By being classified as a safety service additional obligations are placed on administrations to take special measures to ensure they are free from interference. This requirement, however, only applies to administrations who wish to provide/take advantage of such a service and to other administrations outside of their national borders. Within an administration’s borders an administration, if it so desires, under RR Article 4.4 can use the frequency bands for another purpose provided as previously indicated, it protects the use of the radionavigation-satellite system outside of its border.

2.5  To further complicate the situation, in a majority of administrations, frequency bands allocated to the radionavigation-satellite service and the systems themselves are not under the control of the aviation authorities and normally under the control of the military authorities. This can lead to issues since the military authorities insist on testing the capability of their systems to resist interference which if not properly co-ordinated can, during the period of the testing, interfere with civil aeronautical use of the systems.

2.6  Additionally due to the number of applications for tracking either objects or people, there is an interest by various parties including the criminal element to either deny or spoof radionavigation-satellite systems in order to avoid those objects being tracked. Reasons for people wishing to avoid objects or themselves being tracked vary from those who fear kidnap or carjacking, through those who want to avoid awkward questions about the delivery routes they take to the criminals who wish to avoid objects they are stealing being tracked. This has resulted in an industry, both legal and illegal, producing jammers that are sold through various outlets including e-bay to those willing to buy them.

2.7  The actions proposed in the State letter mentioned in paragraph 2.3 will help to address a number of the potential causes of interference to aeronautical use of radionavigation-satellite systems, but they cannot address every potential cause especially those related to illegal activities. As a result aviation should not only take the actions listed in the State letter but also review its own policies and intentions with respect to the use of radionavigation satellite systems.

3.  Conclusion

·  Radionavigation-satellite systems, such as GPS provide a means of location and timing information on a global basis.

·  The systems operate in common frequency bands which are not controlled by aviation authorities

·  These systems have not been designed solely for the use of civil aviation, with the current generation of operational systems being developed and operated by the military primarily for military purposes.

·  The number of civil including aeronautical applications is ever.

·  As applications are developed allowing the location of either a person or an object so denying access to or spoofing such signals is becoming ever more interesting to those who would wish to protect the identification of the location of that person or object and hence the use of jammers is ever increasing.

·  Since the systems were developed for military applications so the military also have an operational need to test their resilience to jamming.

·  The actions by States proposed in the State letter sent by ICAO will help further reduce interference caused by legal activities such as military jamming however it will not improve the situation with respect to illegal jamming except maybe reduce the time to resolution although that is debateable.

·  Aviation in the design of its systems, through ICAO and the relevant panels, take into account the vulnerability of Radionavigation-satellite systems to interference as well as any common mode failure issues.

4.  Recommended action by the meeting

4.1  The meeting is invited to:-

·  note the content of this paper;

·  encourage their States to take all relevant action to ensure the protection of radionavigation-satellite systems;

·  to inform other relevant panels of the problems with respect to ensuring the protection of radionavigation-satellite systems and suggest they may wish to review their policies with respect to the use of such systems especially where it is intended that they will be a sole means of providing a service.

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