7 Necessary and secure infrastructure
Illustration: Inok
Secure and efficient infrastructure is fundamental for aviation and use of the airspace. In the field of aviation, a transition is underway from traditional and ground-based systems to digital and often satellite-based systems (Global Navigation Satellite Systems, GNSS). This is a result of technological developments and ICAO’s and the EU’s requirements for the introduction of Performance-based navigation (PBN). The EU requirements are also set out in Regulation (EU) 2018/1048, which Norway has also implemented. The use of GNSS and PBN offer improved use of the airspace and contribute to more efficient and environmentally friendly aviation. At the same time, there are potential security and vulnerability aspects involved in the considerable GNSS dependency.
7.1 Communication, navigation and surveillance
Communication, Navigation and Surveillance (CNS) relates to the installation, operation and maintenance of facilities for communication with, navigation for and surveillance of air traffic.
Historically, such facilities have been physical installations such as radio transmitters/receivers and antennae on the ground that have exchanged data and been in contact with equipment on board the aircraft. These ground-based, conventional facilities are now increasingly being replaced by satellite-based services (GNSS).
In addition to GNSS for positioning and navigation on board planes/aircraft, airspace surveillance and communication is increasingly also based on GNSS as a source of position and time synchronisation.
Satellites and their signals have a universal problem. They are far from the earth’s surface and there is a limited transmission power. This means that the signal is relatively weak and possible to drown out. In case of jamming, the CNS services will to varying degrees cease unless other infrastructure independent of GNSS is available. We are now at a crossroads for all CNS services, where digitalisation and use of satellite-based services will be exclusively used in normal operations. The advantage of such satellite-based services is an unsurpassed precision, accessibility and low costs for users. This enables e.g., shorter and more precise approach procedures, as well as the possibility to arrange for approaches outside of densely populated areas. However, there is a vulnerability and failure probability involved in these systems that one must be aware of and willing to accept.
In accordance with the requirements in 2018/1048 concerning performance-based navigation, Avinor has prepared a PBN transition plan. This plan describes the phasing out of conventional approach instruments at Norwegian airports in the period leading up to 2030. The plan assesses the extent to which conventional systems should be maintained as a back-up solution to support aviation in case of GNSS outages. The ground-based, conventional facilities are owned and operated by airports and air navigation suppliers, and the costs of procurement, installation and operation have been charged to airspace users through a take-off fee and fees for air navigation services that are expected to be reduced in the future. If needs in local communities or preparedness considerations indicate a desire to retain conventional systems, it has to be considered who will then bear the additional costs for these. If these additional costs are borne by the air navigation service suppliers or airport operators, the EU legislation will limit the possibility to charge a fee for maintenance. The costs of retaining conventional systems for safeguarding national needs for infrastructure and services beyond civil needs, should be borne by the parties that have such needs.
7.2 The PNT Strategy: overarching and coordinating
PNT systems is the common name for ground-based and satellite-based systems (GNSS) for positioning, navigation and timing. Failure of PNT services may, among other things, be due to disruptions of GNSS signals caused by natural and manmade sources and may in the latter case be unintentional or targeted.
The PNT Strategy Right place, right time. The National Strategy for positioning, navigation and timing, 13 which was presented in November 2018, is part of the Norwegian Government’s work on strengthening public security and facilitating technological development. The Strategy addresses sectoral authorities at various administrative levels, as well as developers, suppliers and users of PNT systems and services. The Strategy reviews PNT systems and how they are used in various parts of society and proceeds to assess vulnerabilities to failure. On this basis, measures are identified to reduce vulnerabilities.
The main objectives for the Strategy are to ensure that we are able to benefit from use of the PNT systems and utilise new opportunities provided by the systems, contribute to awareness raising regarding society’s dependence on PNT systems, and contribute to the reduction of society’s vulnerabilities relating failure of PNT systems through preventive measures and preparedness.
7.3 Navigation strategy for aviation in Norway
The growth in air traffic entails that higher requirements must be set in terms of how accessible airspace is used. At the same time as a high safety level must be maintained, measures have to be initiated that contribute to increased capacity and efficiency in the air traffic management system; not just nationally, but throughout the pan-European network. To ensure the optimal effect of the measures, it is important that as many actors as possible apply identical and harmonised requirements. This occurs in the EU area through the common European regulations mentioned above concerning performance-based navigation, Regulation (EU) 2018/1048.
In parallel with the adoption of this Regulation, ICAO and the EU have, at the global and regional levels, respectively, encouraged member states to create their own navigation strategies. The Norwegian Navigation Strategy was established by the Ministry of Transport on 11 December 202014.
The work on the Navigation Strategy also includes risk assessments of the vulnerabilities in aviation and risk assessments performed by Avinor, including vulnerabilities in the air navigation services. Avinor’s perception is that aviation as a whole is moving in the direction of an everyday situation where the consequences of GNSS outages will become increasingly problematic.
The PBN Regulation determines that conventional procedures shall not be used after 2030. Therefore, it is a target to reduce local, conventional air navigation facilities by reducing the scope thereof in the coming decade. This will render the navigation function especially vulnerable in terms of outages, and for some types of planes in the current fleet.
However, the PBN Regulation contains exemption possibilities to ensure necessary operation of air navigation services. In this connection, the Regulation mentions in particular the possibility to maintain a network of conventional navigation aids and associated surveillance and communication infrastructure. Therefore, the plan is to retain conventional systems and instrument procedures at airports and in airspaces of national and regional importance. The more detailed solutions are stated in the transition plan prepared by Avinor.
7.4 National capability for airspace surveillance
The developments in civil aviation challenge the military capability to carry out national airspace surveillance. The reasons for this are two-fold. Firstly, the Norwegian Armed Forces’ chain of surveillance radars with primary radar coverage has been gradually reduced over the past 10-20 years, since the majority of the sensors have passed their expected lifespan, and replacements have been delayed. This radar chain shall have the capability to detect all types of flying objects in the airspace (uncooporative targets) with the aid of traditional radar technology. A project for the implementation of new sensors is underway and will be completed by 2030.
Second, Avinor has established a new position monitoring system, based on installations on the ground that coordinate signals transmitted by the aircraft (Wide Area Multilateration, WAM) with a future implementation of ADS-B (Automatic Dependent Surveillance – Broadcast) as a supplement. This has resulted in the need for conventional primary and secondary radars to be gradually phased out in civil aviation, with the exception of Oslo Airport.
The consequence of this development is that the Norwegian Armed Forces has to a lesser extent been able to base its work on the civil air traffic services’ equipment to carry out national airspace surveillance.
7.5 GNSS/GPS disruptions in aviation
The most known GNSS systems are GPS (U.S.), which is also the most used, GLONASS (Russia), Beidou (China) and gradually also Galileo (EU), which is the system where Norway is participating. The systems are owned and controlled by the aforementioned states, which are thereby in a controlling/dominant position for critical infrastructure internationally.
Norwegian aviation experienced prolonged GPS interference from the Russian side of the border in 2018, where Northern Norway was especially exposed. The Norwegian Government took these disruptions seriously and decided in 2019 to establish a working group under the auspices of the Ministry of Transport. The Working Group was tasked with identifying and assessing threats and risks, impacts and handling relating to GNSS disruptions, especially the impact of the GPS system in aviation. The Working Group presented the report GNSS/GPS-disruptions in aviation in December 201915.
At the overarching/policy level, the message of the report is that Norwegian authorities do not have ownership or control of GNSS/GPS-systems, and that Norwegian authorities’ scope of action is therefore limited.
The report recommends openness and awareness raising regarding possibilities and limitations with the use of GNSS systems, the necessity of back-up systems and alternatives, as well as a conscious attitude regarding the vulnerabilities/risks one is willing to take. Prevention of unwanted occurrences is most important, but the report also emphasises the further development and continuous updating of notification procedures and plans and tools for restoration following disruptions. Measures must also be facilitated within each sector, but also across sectors, e.g., through an operations centre under the auspices of the Norwegian Communications Authority (Nkom). The report also devotes considerable attention to measures to limit/prevent the use of jammers.
Another point in the report includes a description of the complexity of the infrastructure in the area of air navigation, where one depends on a common time reference in order for the systems to function optimally. GNSS-based time synchronisation is a simple and inexpensive way to ensure the same time everywhere in a distributed system, but this also involves a vulnerability if GNSS is the only time source. In order to improve redundancy in the air navigation systems, Avinor will procure atomic clocks for time synchronisation that are not dependent on GNSS.
The report summarises that one should not prevent technological developments but be aware of the balance between the use of modern and digitalised technology and the understanding of vulnerabilities.
As a follow-up, it was decided that the Ministry of Transport would incorporate the report on GNSS/GPS disruptions into its work on a Norwegian Airspace Strategy, at the same time as each government ministry has an independent responsibility for follow-up within their areas of responsibility.
Regarding the High North, and especially in relation to GNSS/GPS disruptions on the part of Russia, it follows from the report that the use of GNSS-based navigation systems is particularly vulnerable. This has to do with the fact that disruptions and outages of necessary infrastructure for aviation may have especially serious consequences for the High North, because of the considerable distances and few or no alternative forms of transport. The report does not examine alternative solutions in-depth, but the establishment or maintenance of certain conventional surveillance/navigation instruments in parts of Finnmark may be a sensible measure to safeguard airspace users. This also applies to Svalbard.
7.6 Frequency disruptions
Nkom, which is the electronic communication authority jointly with the Ministry of Local Government and Modernisation, has over several decades followed up frequency use that causes disruptions of electronic communication services. Nkom wishes to formalise this work to a greater extent through the establishment of a radio interference centre. Since early 2020, Nkom has used disruptions of navigation signals (e.g., GPS) as a “pilot” for how a radio interference centre can function in practice, with special attention given to the establishment of rapid and reliable notification channels and procedures.
In the cases that have occurred involving disruptions of GPS in aviation, Nkom has had especially close contact with Avinor, the Civil Aviation Authority of Norway and the Ministry of Local Government and Modernisation.
In situations where the sources of the disruption are found in other countries, Nkom documents the facts and addresses the case at the ministerial level for assessment and follow-up.
Nkom has legal bases in the Electronic Communications Act to shut down jammers and other equipment that result in disruption or blocking of services for electronic communication that threaten lives, health and safety. Currently, Nkom does not have any legal basis for stopping the sale of jammers or confiscating jammers that are not actively in use.
Norwegian authorities consider it important to highlight Norwegian experiences with GNSS/GPS disruptions in international, regional and bilateral aviation contexts, with a view of developing good solutions for critical infrastructure in the field of aviation and airspace use.
7.7 Strategy
The Norwegian Government will:
- Facilitate in order for systems that underpin preparedness functions in the airspace to have sufficient protection and redundancy in order to ensure continued operations following possible outages or compromising of civil computer networks, GPS signals etc.
- Ensure that Norway, together with other European countries, follows up the problems relating to GNSS disruptions in aviation in relation to ICAO in a joint European initiative on GNSS disruptions and vulnerabilities.
- Actively follow-up the development of technologies and services relating to the special conditions for aviation in the High North, in order to support the state’s strategic efforts and needs.
- Ensure that the national capability for airspace monitoring is viewed from a Total Defence perspective.