Pub Date : 2018-12-01DOI: 10.1109/NAVITEC.2018.8642661
G. Caparra, N. Laurenti
Many proposals for GNSS anti-spooting have been presented by the research community in the past decade. Some operate at the receiver side, for instance by exploiting advanced signal processing algorithms, or by making use of additional information, such as that coming from inertial sensors, as a means to detect, and possibly mitigate, interferences and spoofing attacks. Another class of mechanisms, instead, foresee the introduction of new features into the GNSS signals, in order to make it harder to mount spoofing attacks, and make it easier for the reciever to detect them. This paper focuses on the possible use of CSK as an anti-spoofing mechanism, that was proposed for GNSS. In this context, the benefits of this modulation choice to the cryptographic integrity protection of the GNSS signal are taken for granted, on the grounds of its higher symbol cardinality and unpredictability. However a quantitative evaluation of such advantage was never carried out. Our aim is to investigate to what extent CSK is beneficial agains spoofing, evaluating the increase in the necessary attack complexity, and showing results obtained with GNSS simulators and software receivers.
{"title":"On the Use of CSK for GNSS Anti-Spoofing","authors":"G. Caparra, N. Laurenti","doi":"10.1109/NAVITEC.2018.8642661","DOIUrl":"https://doi.org/10.1109/NAVITEC.2018.8642661","url":null,"abstract":"Many proposals for GNSS anti-spooting have been presented by the research community in the past decade. Some operate at the receiver side, for instance by exploiting advanced signal processing algorithms, or by making use of additional information, such as that coming from inertial sensors, as a means to detect, and possibly mitigate, interferences and spoofing attacks. Another class of mechanisms, instead, foresee the introduction of new features into the GNSS signals, in order to make it harder to mount spoofing attacks, and make it easier for the reciever to detect them. This paper focuses on the possible use of CSK as an anti-spoofing mechanism, that was proposed for GNSS. In this context, the benefits of this modulation choice to the cryptographic integrity protection of the GNSS signal are taken for granted, on the grounds of its higher symbol cardinality and unpredictability. However a quantitative evaluation of such advantage was never carried out. Our aim is to investigate to what extent CSK is beneficial agains spoofing, evaluating the increase in the necessary attack complexity, and showing results obtained with GNSS simulators and software receivers.","PeriodicalId":355786,"journal":{"name":"2018 9th ESA Workshop on Satellite NavigationTechnologies and European Workshop on GNSS Signals and Signal Processing (NAVITEC)","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117027143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1109/NAVITEC.2018.8642697
C. Fernández-Prades, J. Arribas, M. Majoral, A. Ramos, J. Vilà‐Valls, P. Giordano
This paper reports the design, proof-of-concept implementation and preliminary performance assessment of a low-cost, software-defined spaceborne GNSS receiver. The presented approach takes advantage of the flexibility of software-defined radio technology and the forthcoming availability of radiation-hardened, space-certified Systems-on-Module to implement a fully customizable receiver with the capability to process GNSS signals in real-time and to deliver GNSS products in standard formats. The core GNSS engine is based on a free and open source software implementation of a multi-band, multi-system GNSS receiver released under the General Public License v3.0 and available in a public source code repository.
{"title":"A Software-Defined Spaceborne GNSS Receiver","authors":"C. Fernández-Prades, J. Arribas, M. Majoral, A. Ramos, J. Vilà‐Valls, P. Giordano","doi":"10.1109/NAVITEC.2018.8642697","DOIUrl":"https://doi.org/10.1109/NAVITEC.2018.8642697","url":null,"abstract":"This paper reports the design, proof-of-concept implementation and preliminary performance assessment of a low-cost, software-defined spaceborne GNSS receiver. The presented approach takes advantage of the flexibility of software-defined radio technology and the forthcoming availability of radiation-hardened, space-certified Systems-on-Module to implement a fully customizable receiver with the capability to process GNSS signals in real-time and to deliver GNSS products in standard formats. The core GNSS engine is based on a free and open source software implementation of a multi-band, multi-system GNSS receiver released under the General Public License v3.0 and available in a public source code repository.","PeriodicalId":355786,"journal":{"name":"2018 9th ESA Workshop on Satellite NavigationTechnologies and European Workshop on GNSS Signals and Signal Processing (NAVITEC)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129644905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1109/NAVITEC.2018.8653644
G. Pojani, Yazan Abdoush, M. Bartolucci, J. García-Molina, G. Corazza
Jammers pose a threat to the reliability of satellite navigation systems. The vast majority of these devices generate broadband interference by rapidly sweeping wide bandwidths with continuous waves. Their waveforms fall into the set of nonstationary signals that can be conveniently analysed through timefrequency transforms. Based on a novel use of the S-transform, the present paper describes a framework for estimating the modulation characteristics of multiple jammers and therewith the respective locations. The performance are evaluated by means of numerical simulations for two jammers. When the jamming waveforms are well characterized, the locations of their sources can be estimated by trilateration with accuracies below ten meters within a square area of side of one kilometre.
{"title":"Multiple jammer localization and characterization based on time-frequency analysis","authors":"G. Pojani, Yazan Abdoush, M. Bartolucci, J. García-Molina, G. Corazza","doi":"10.1109/NAVITEC.2018.8653644","DOIUrl":"https://doi.org/10.1109/NAVITEC.2018.8653644","url":null,"abstract":"Jammers pose a threat to the reliability of satellite navigation systems. The vast majority of these devices generate broadband interference by rapidly sweeping wide bandwidths with continuous waves. Their waveforms fall into the set of nonstationary signals that can be conveniently analysed through timefrequency transforms. Based on a novel use of the S-transform, the present paper describes a framework for estimating the modulation characteristics of multiple jammers and therewith the respective locations. The performance are evaluated by means of numerical simulations for two jammers. When the jamming waveforms are well characterized, the locations of their sources can be estimated by trilateration with accuracies below ten meters within a square area of side of one kilometre.","PeriodicalId":355786,"journal":{"name":"2018 9th ESA Workshop on Satellite NavigationTechnologies and European Workshop on GNSS Signals and Signal Processing (NAVITEC)","volume":"271 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122173423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1109/NAVITEC.2018.8642706
A. Poltronieri, G. Caparra, N. Laurenti
The Chimera scheme was proposed in [1] for protecting the GPS L1C signal by inserting random markers at the chip level in the spreading code. Rather than being uniformly distributed, the markers’ positions are set by picking one pattern out of m=256 in a predetermined, publicly known lookup table, possibly for efficiency reasons. This work analyzes the Chimera scheme, focusing on the lookup table to evaluate whether this structure affects the security of the system. In particular, we compare it with an ideal uniform distribution of the markers in terms of their robustness against guessing and collision attacks. We then proceed analyzing other possible attack strategies, calculating or lower bounding their success probabilities, and finally validate the result through comparisons with Monte Carlo simulations.
{"title":"Analysis of the Chimera Time-Binding Scheme for Authenticating GPS L1C","authors":"A. Poltronieri, G. Caparra, N. Laurenti","doi":"10.1109/NAVITEC.2018.8642706","DOIUrl":"https://doi.org/10.1109/NAVITEC.2018.8642706","url":null,"abstract":"The Chimera scheme was proposed in [1] for protecting the GPS L1C signal by inserting random markers at the chip level in the spreading code. Rather than being uniformly distributed, the markers’ positions are set by picking one pattern out of m=256 in a predetermined, publicly known lookup table, possibly for efficiency reasons. This work analyzes the Chimera scheme, focusing on the lookup table to evaluate whether this structure affects the security of the system. In particular, we compare it with an ideal uniform distribution of the markers in terms of their robustness against guessing and collision attacks. We then proceed analyzing other possible attack strategies, calculating or lower bounding their success probabilities, and finally validate the result through comparisons with Monte Carlo simulations.","PeriodicalId":355786,"journal":{"name":"2018 9th ESA Workshop on Satellite NavigationTechnologies and European Workshop on GNSS Signals and Signal Processing (NAVITEC)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132783783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1109/NAVITEC.2018.8642663
M. Gamba, E. Falletti
In the field of Global Navigation Satellite System (GNSS), jamming signals are more than ever a real threat, demanding for an increasing need of countermeasures. Among several proposed detection and mitigation methods developed for specific types of interference, the Adaptive Notch Filter (ANF) is still an attractive solution to mitigate very narrowband interference signals, for its ease of implementation, low computational cost and reduced activation time. ANFs have been widely exploited in literature, with many variations: albeit well known to be particularly effective for Continuous Wave (CW) interferes, an early proof of their suitability also against certain types of GNSS jammers has been shown. In this paper, two recently proposed Frequency Lock Loop (FLL) models to implement the adaptive capability of the ANF are considered: the standard FLL and the FLL with exponential filtering. While both have already been analyzed in the presence of CW interfering signals, with constant carrier frequency, here an evaluation in case of fast sweeping central frequency is conducted, targeting the features of some of the most common jammers detected in the GPS LI/Galileo E1 band. A comparison in terms of tracking capability and noise performance is presented. While the standard FLL shows to be able to successfully track and mitigates jamming signals, the exponential filtering FLL proves it is not up to, suffering particularly from frequency discontinuities, which commonly characterize such kind of interferers.
{"title":"Performance Analysis of FLL Schemes to Track Swept Jammers in an Adaptive Notch Filter","authors":"M. Gamba, E. Falletti","doi":"10.1109/NAVITEC.2018.8642663","DOIUrl":"https://doi.org/10.1109/NAVITEC.2018.8642663","url":null,"abstract":"In the field of Global Navigation Satellite System (GNSS), jamming signals are more than ever a real threat, demanding for an increasing need of countermeasures. Among several proposed detection and mitigation methods developed for specific types of interference, the Adaptive Notch Filter (ANF) is still an attractive solution to mitigate very narrowband interference signals, for its ease of implementation, low computational cost and reduced activation time. ANFs have been widely exploited in literature, with many variations: albeit well known to be particularly effective for Continuous Wave (CW) interferes, an early proof of their suitability also against certain types of GNSS jammers has been shown. In this paper, two recently proposed Frequency Lock Loop (FLL) models to implement the adaptive capability of the ANF are considered: the standard FLL and the FLL with exponential filtering. While both have already been analyzed in the presence of CW interfering signals, with constant carrier frequency, here an evaluation in case of fast sweeping central frequency is conducted, targeting the features of some of the most common jammers detected in the GPS LI/Galileo E1 band. A comparison in terms of tracking capability and noise performance is presented. While the standard FLL shows to be able to successfully track and mitigates jamming signals, the exponential filtering FLL proves it is not up to, suffering particularly from frequency discontinuities, which commonly characterize such kind of interferers.","PeriodicalId":355786,"journal":{"name":"2018 9th ESA Workshop on Satellite NavigationTechnologies and European Workshop on GNSS Signals and Signal Processing (NAVITEC)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133351368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-01DOI: 10.1109/NAVITEC.2018.8642702
F. Nunes, F. Sousa, Jose M. V. Marcal
A fast technique to simulate the effect of equatorial ionospheric scintillation on GNSS signals was proposed by the authors in a previous work. The algorithm uses a single-layer phase-screen model of the ionosphere and the scintillation is expressed by the Huygens-Fresnel (HF) integral which can be determined analytically. Herein, we characterize statistically the amplitude and phase obtained with the HF integral for different values of the scintillation index S4. A phase unwrapper is also developed to determine the phase from the modulo two-pi version provided by the argument of the HF integral.
{"title":"Statistical Characterization of Ionospheric Scintillation using a Phase-screen Model","authors":"F. Nunes, F. Sousa, Jose M. V. Marcal","doi":"10.1109/NAVITEC.2018.8642702","DOIUrl":"https://doi.org/10.1109/NAVITEC.2018.8642702","url":null,"abstract":"A fast technique to simulate the effect of equatorial ionospheric scintillation on GNSS signals was proposed by the authors in a previous work. The algorithm uses a single-layer phase-screen model of the ionosphere and the scintillation is expressed by the Huygens-Fresnel (HF) integral which can be determined analytically. Herein, we characterize statistically the amplitude and phase obtained with the HF integral for different values of the scintillation index S4. A phase unwrapper is also developed to determine the phase from the modulo two-pi version provided by the argument of the HF integral.","PeriodicalId":355786,"journal":{"name":"2018 9th ESA Workshop on Satellite NavigationTechnologies and European Workshop on GNSS Signals and Signal Processing (NAVITEC)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125352518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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