Vulnerability Of Global Navigation Satellite Systems Research Articles

Analysis of the impact of GNSS disruptions on aircraft operations at Romanian airports

In the transition towards space-based air navigation, the reliance on Global Navigation Satellite Systems (GNSS) is increasing. However, GNSS disruptions and interference can cause GPS loss in the cockpit. The purpose of this paper is to assess the impact of GNSS vulnerabilities, especially interference, on aircraft operations. The data used for this analysis was collected by GNSS monitoring stations installed at two Romanian airports, specifically selected due to their proximity to possible interference sources. In order to obtain relevant results, the entire assessment is based on the scenario in which all the flights at the airport are using GNSS as their primary means of navigation. Therefore, the flights that could have possibly been affected were identified and the operational impact of interference was assessed. This study emphasises the importance of GNSS monitoring at airports in order to reduce the negative effects of GNSS disruptions on the safe and efficient operations of aircraft.

ЗАБЕЗПЕЧЕННЯ СТІЙКОЇ РОБОТИ СУПУТНИКОВОЇ НАВІГАЦІЇ НА МОРІ

The article examines the challenges of global navigation satellite systems (GNSS) functioning at sea under unintentional and intentional interference. The article reviews the vulnerability of GNSS, the methods of protection against interference and the ways of mitigating their impact based on the marine concept of positioning, navigation and time synchronization (PNT). The main goal of this concept is the guaranteed obtaining of reliable data on coordinates, navigation and exact time due to the combined use and comparison of indication for disparate systems and sensors under the influence of natural or intentional interference (attacks) on ship's GNSS equipment. The article analyzes various open sources of information to identify two methods of ensuring the integrity and accuracy of PNT data according to IMO documents and standards. The first method is the detection and direct countermeasures against attacks on shipboard GNSS equipment. The article determines that the most common and easy-to-implement type of attacks are jamming attacks of satellite signals, unlike the more complex and challenging spoofing attacks. The main approach to protection against jamming attacks is spatial signal processing using adaptive marine antenna arrays with a controlled pattern. Examples of modern practical developments of adaptive antenna arrays are given. The second method to ensure reliable PNT data is the use of alternative navigation systems, redundant capabilities and non-traditional methods using the existing systems. Technical solutions in this method have limitations due to the requirements for the vessel’s conventional navigation and radio communication installation. IMO has suggested structures of multisensor and multisystem receivers for obtaining reliable PNT data. These structures combine primary data from different systems based on different principles, such as satellite, terrestrial and augmented correction systems, vessel navigation data and reference systems. The processed PNT data must be accompanied by accuracy and integrity indicators. Keywords: positioning, navigation, time synchronization, jamming, spoofing, spatial processing, antenna arrays, cyber risks, information protection.

Authenticated Timing Protocol Based on Galileo ACAS.

Global navigation satellite systems (GNSSs) provide accurate positioning and timing services in a large gamut of sectors, including financial institutions, Industry 4.0, and Internet of things (IoT). Any industrial system involving multiple devices interacting and/or coordinating their functionalities needs accurate, dependable, and trustworthy time synchronization, which can be obtained by using authenticated GNSS signals. However, GNSS vulnerabilities to time-spoofing attacks may cause security issues for their applications. Galileo is currently developing new services aimed at providing increased security and robustness against attacks, such as the open service navigation message authentication (OS-NMA) and commercial authentication service (CAS). In this paper, we propose a robust and secure timing protocol that is independent of external time sources, and solely relies on assisted commercial authentication service (ACAS) and OS-NMA features. We analyze the performance of the proposed timing protocol and discuss its security level in relation to malicious attacks. Lastly, experimental tests were conducted to validate the proposed protocol.

GNSS Vulnerabilities and Existing Solutions: A Review of the Literature

This literature review paper focuses on existing vulnerabilities associated with global navigation satellite systems (GNSSs). With respect to the civilian/non encrypted GNSSs, they are employed for proving positioning, navigation and timing (PNT) solutions across a wide range of industries. Some of these include electric power grids, stock exchange systems, cellular communications, agriculture, unmanned aerial systems and intelligent transportation systems. In this survey paper, physical degradations, existing threats and solutions adopted in academia and industry are presented. In regards to GNSS threats, jamming and spoofing attacks as well as detection techniques adopted in the literature are surveyed and summarized. Also discussed are multipath propagation in GNSS and non line-of-sight (NLoS) detection techniques. The review also identifies and discusses open research areas and techniques which can be investigated for the purpose of enhancing the robustness of GNSS.

Providing a Resilient Timing and UTC Service Using eLoran in the United States

More and more systems are becoming solely dependent on GPS or other Global Navigation Satellite Systems (GNSS) for their precise position, timing, and frequency information. Along with this explosive growth comes an increasing awareness of GNSS vulnerabilities such as interference, jamming, and spoofing. eLoran is a high-power, low-frequency, ground-wave radio broadcast system, capable of providing 10-meter positioning accuracy, Stratum-1 frequency distribution, and UTC timing well within 1 μs across very large areas (1,000 mi). Application of differential corrections for timing further improves the accuracy to better than 100 ns. eLoran is a proven technology, well established for providing services very similar to those delivered by GNSS, with characteristics and failure modes that are complementary to GNSS. This paper discusses the general concept of eLoran timing and UTC distribution, and the current prototype service. It highlights plans for an initial four-station CONUS-wide timing service, which can be expanded to provide increased coverage and redundancy and deeper penetration into buildings. Additional stations enable positioning and navigation services. Copyright © 2017 Institute of Navigation

Interference Localization for Satellite Navigation Systems

Global navigation satellite systems (GNSS) and, in particular, the global positioning system (GPS) have become ubiquitous in safety critical infrastructure. Vulnerability of GNSS to radio frequency interference (RFI) from either intentional (jamming) or unintentional sources is an ever growing concern. Hence, GNSS itself has become critical infrastructure which must be protected and its vulnerability to interference alleviated. As the RFI source is unknown a priori , passive localization systems are required; this adds an order of difficulty when compared with transmitter location systems with known and cooperative sources. The need for rapidly localizing the RFI leads to sensor network techniques which consist of spatially distributed sensor nodes (SNs). The localization systems typically use the received signal strength (RSS), source angle of arrival (AOA)/ direction of arrival (DOA), time difference of arrival (TDOA) or a combination of AOA(DOA)/TDOA or frequency difference of arrival (FDOA) measurements to estimate the RFI position. This paper provides an overview of existing systems from the literature and a comparison of these different interference geo-localization techniques.

Quantitative Assessment of GNSS Vulnerability based on D-S Evidence Theory

With the increasing attention paid to Global Navigation Satellite System (GNSS) vulnerability, there is an urgent need to develop a systemic and feasible approach to weight the GNSS vulnerability degree. A novel model of quantitative assessment for GNSS vulnerability relying on several predefined metrics of vulnerability performance is proposed to measure the impact of vulnerability factors on service availability. This model applies the theory of Dempster-Shafer evidence reasoning to fuse three metrics of vulnerability performance, which are designed carefully to reflect the reliability of service availability in three different perspectives. This model includes three steps: determining performance metrics, calculating vulnerability index and characterizing the vulnerability state of service availability. This approach chooses metrics from the system’s point of view, ignores the more abstract attributes of vulnerability factors but seeks concrete observables, calculates quantitative vulnerability index and provides evolution of vulnerability state over time. Experiments based on GNSS vulnerability physical simulation, verification platform established in our lab show that this method measures the vulnerability index accurately. Moreover, it lays the foundation for future threat inferences and remedy operations under the influence of vulnerability.

A case for assisted partial timing support using precision timing protocol packet synchronization for LTE-A

North American service providers are in the process of upgrading their radio access networks with next generation LTE equipment. They are finalizing a 4G rollout that involves highly stringent timing requirements, but in many cases they are relying on sole-source synchronization by using Global Navigation Satellite System (GNSS). Natural occurring disturbances, as well as unintentional radio frequency jamming, intentional jamming, and spoofing, make GNSS vulnerable to interference. This article presents a novel approach for addressing the issue of GNSS vulnerability by introducing a standard means of providing a redundant packet-based synchronization source for LTE base stations. It also describes how this new approach can mitigate noise caused by asymmetry and transit delay variation in packet networks.

GNSS Vulnerability Analysis and Assessment

A Global Navigation Satellite System (GNSS) vulnerability assessment approach based on separately detecting possible factors is developed in this paper. The consistency judgment of visible satellites and navigation message, carrier-to-noise ratio (C/No), Satellite Autonomous Integrity Monitoring (SAIM), Receiver Autonomous Integrity Monitoring (RAIM), Ionosphere delay and Receiver’s Position error are chosen as key features to detect whether the GNSS vulnerability is serious. By monitoring those key features, potential vulnerability factor can be excluded in steps. This approach is established in clearly elaborating the concept of GNSS vulnerability and fully analyzing the potential vulnerability factors in system segment, environment segment and user segment. A GNSS vulnerability physical simulation, verification and mitigation platform is also designed; the establishment of this platform is a future work to realize this approach and to mitigate the vulnerability while it happens.

GNSS vulnerabilities: simulation, verification, and mitigation platform design

This paper introduces the design and construction of global navigation satellite systems (GNSS) vulnerability simulation, verification, and mitigation platform. The platform contains five modules: simulation of the signal-in-space environment, simulation of the vulnerabilities in the space segment, signal quality monitoring and data processing, vulnerability assessment and validation, and integrated control. It provides a set of integrated simulations of different types of interference in the GNSS signal propagation domain, including electromagnetic interference, atmospheric disturbances, multipath, and interference in the inter-satellite link. This paper focuses on the design of the main system modules and testing through an experimental analysis. The results demonstrate both the effectiveness and realism of the modules and overall platform.

GPS Jamming and the Impact on Maritime Navigation

Versions of this paper were first presented at the Royal Institute of Navigation GNSS Vulnerabilities and Solutions Conference held at Baska, Croatia in September 2008 and the Royal Institute of Navigation NAV 08 Conference held at Church House, Westminster, London in October 2008.The US Global Positioning System (GPS) is currently the primary source of Position, Navigation and Timing (PNT) information in maritime applications, whether stand-alone or augmented with additional systems. This situation will continue in the future with GPS, possibly together with other Global Navigation Satellite Systems (GNSS) e.g. Galileo, being the core PNT technology for e-Navigation – the future digital maritime architecture. GPS signals, measured at the surface on the Earth, are very weak. As such, the system is vulnerable to unintentional interference and jamming, resulting in possible denial of service over large geographical areas. The result of such interference could be the complete failure of the mariner's GPS receiver or, possibly worse, the presentation to the mariner of hazardously misleading information (HMI) for navigation and situational awareness, depending on how the GPS receiver reacts to the jamming incident. Recognising this, the General Lighthouse Authorities of the United Kingdom and Ireland (GLA), in collaboration with the UK Ministry of Defence (MOD) Defence Science and Technology Laboratory (DSTL), have conducted a series of sea-trials with the aim of identifying the full effects of GPS jamming on safe navigation at sea.This paper presents the key findings of these trials and provides important information on the effect of GPS denial. The GLA are playing a pivotal role in the establishment of eLoran as an independent source of PNT, taking advantage of eLoran's complementary nature, having dissimilar failure modes to GPS and the future GNSS. This paper provides information on the performance of an eLoran receiver in an area of GPS service denial. The paper presents the rationale for the work, details the system architecture employed, the data gathering efforts and finally the data analysis procedures, results and conclusions.

The Potential Impact of GNSS/INS Integration on Maritime Navigation

A version of this paper was presented at ENC-GNSS 2007, Geneva. Its reproduction was kindly authorised by the ENC-GNSS 07 Paper Selection Committee.The General Lighthouse Authorities of the UK & Ireland commissioned an assessment of the impact that the integration of Global Navigation Satellite Systems (GNSS) with Inertial Navigation Systems (INS) would have on the aids to navigation (AtoN) services currently provided, and those to be provided in the future. There is concern about the vulnerability of GNSS, and the provision of complementary and backup systems is seen to be of great importance. The integration of INS could provide an independent and self-contained navigation system, for a limited time period, invulnerable to external intentional or unintentional interference, or the influences of changes in national policies. The study included an analysis of the potential use of GNSS-INS in three of the four phases of a vessel's voyage: coastal, port approach and docking. The project consisted of a technology assessment, looking at the different inertial technologies that might be suitable for each phase. This was followed by a technology proving stage, evaluating suitable equipment using simulation and field trials to prove that the claimed performance could be achieved in practice. The final stage of the project was to assess the effects of the availability of such systems on existing and planned aids to navigation services.