Alexander Rügamer

Alexander Rügamer
Fraunhofer Institute for Integrated Circuits | IIS · Department of Satellite Based Positioning Systems

Doctor of Engineering

About

100
Publications
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640
Citations

Publications

Publications (100)
Preprint
Full-text available
The accuracy of global navigation satellite system (GNSS) receivers is significantly compromised by interference from jamming devices. Consequently, the detection of these jammers are crucial to mitigating such interference signals. However, robust classification of interference using machine learning (ML) models is challenging due to the lack of l...
Preprint
Full-text available
Jamming devices present a significant threat by disrupting signals from the global navigation satellite system (GNSS), compromising the robustness of accurate positioning. The detection of anomalies within frequency snapshots is crucial to counteract these interferences effectively. A critical preliminary measure involves the reliable classificatio...
Conference Paper
The accuracy and reliability of vehicle localization on roads are crucial for applications such as self-driving cars, toll systems, and digital tachographs. To achieve accurate positioning, vehicles typically use global navigation satellite system (GNSS) receivers to validate their absolute positions. However, GNSS-based positioning can be compromi...
Preprint
Full-text available
The primary objective of methods in continual learning is to learn tasks in a sequential manner over time from a stream of data, while mitigating the detrimental phenomenon of catastrophic forgetting. In this paper, we focus on learning an optimal representation between previous class prototypes and newly encountered ones. We propose a prototypical...
Preprint
Full-text available
Jamming devices pose a significant threat by dis-rupting signals from the global navigation satellite system (GNSS), compromising the robustness of accurate positioning. Detecting anomalies in frequency snapshots is crucial to counter-act these interferences effectively. The ability to adapt to diverse, unseen interference characteristics is essent...
Conference Paper
Full-text available
Jamming devices pose a significant threat by dis-rupting signals from the global navigation satellite system (GNSS), compromising the robustness of accurate positioning. Detecting anomalies in frequency snapshots is crucial to counter-act these interferences effectively. The ability to adapt to diverse, unseen interference characteristics is essent...
Article
Full-text available
Interference signals degrade the performance of a global navigation satellite system (GNSS) receiver. Classification of these interference signals allow better situational awareness and facilitate appropriate countermeasures. However, classification is challenging and processing-intensive, especially in severe multipath environments. This article p...
Article
Full-text available
Spoofing, the transmission of false global navigation satellite system signals, threatens receivers. The first step in dealing with spoofers is to detect the attack. Once a spoofing attack is detected, spatial detection methods using an array of antennas can additionally mitigate spoofing through spatial nulling. This article presents a spatial spo...
Conference Paper
Full-text available
Interference signals from privacy protection devices (PPDs) degrade global navigation satellite system (GNSS) performance and must be mitigated. This article presents practical results with the multi-parameter adaptive notch filter (MPANF) against a commercial-off-the-shelf (COTS) PPD. Additionally, the wavelet-based multi-parameter adaptive notch...
Article
This paper gives an overview over a global navigation satellite system (GNSS) interference detection and classification system developed by the Fraunhofer Institute for Integrated Circuits IIS. Two sensor platforms are presented and their performance and costs compared. An interference detection network consisting of two sensor types is introduced....
Article
Full-text available
Interference signals cause position errors and outages to global navigation satellite system (GNSS) receivers. However, to solve these problems, the interference source must be detected, classified, its purpose determined, and localized to eliminate it. Several interference monitoring solutions exist, but these are expensive, resulting in fewer nod...
Conference Paper
Full-text available
This paper gives an overview over a global navigation satellite system (GNSS) interference detection and classification system developed by the Fraunhofer Institute for Integrated Circuits IIS. Two sensor platforms are presented and their performance and costs compared. An interference detection network consisting of two sensor types is introduced....
Conference Paper
Full-text available
Adaptive notch filters (ANFs) can efficiently mitigate linear chirp signals. However, they are only a subclass of frequency-modulated continuous-wave (FMCW) waveforms. Many other FMCW signals could pose potential threats in the future. This paper evaluates several exotic FMCW waveforms and how mitigateable they are with ANFs. Furthermore, the advan...
Conference Paper
Full-text available
Multipath severely degrades the tracking performance of global navigation satellite system (GNSS) receivers, creating inaccuracy estimates and possibly causing the loss of lock. Previous research shows multiple methods to detect, suppress, mitigate or correct multipath in various receiver processing stages. However, these methods are implemented at...
Conference Paper
Full-text available
The Global Navigation Satellite System (GNSS) community shows great interest in detecting and eliminating GNSS interference, i.e., jammers. State-of-the-art techniques employ either threshold-based mechanisms or supervised learning on raw data streams or features thereof. However, they require special expensive GNSS receiver hardware that needs to...
Conference Paper
Full-text available
Interference signals (i.e., jammers) affect the processing chain of global navigation satellite system (GNSS) receivers, affecting or disrupting their accuracy. State-of-the-art supervised, learning-based methods detect and classify jammers at the highest accuracies. However, they require an elaborate labeling process that is scenario-specific and...
Conference Paper
Full-text available
Spoofing attacks mislead global navigation satellite system (GNSS) receivers into reporting false position, velocity, and time (PVT) solutions. However, not all spoofing attacks are the same: they range from simple meaconers to advanced synchronized spoofers. Classifying the attack improves situational awareness and helps the receiver operator take...
Conference Paper
Full-text available
Interference signals degrade and disrupt Global Navigation Satellite System (GNSS) receivers, impacting their localization accuracy. Therefore, they need to be detected, classified, and located to ensure GNSS operation. State-of-the-art techniques employ supervised deep learning to detect and classify potential interference signals. Here, literatur...
Conference Paper
Full-text available
Interference signals cause position errors and outages to global navigation satellite system (GNSS) receivers. However, to solve these problems, the interference needs to be detected, classified, its purpose determined, and localized, such that it can be eliminated. Several interference monitoring solutions exist, but these are expensive, resulting...
Conference Paper
The aim of the research project HALI-Berlin is to demonstrate the use of Galileo PRS (PRS = Public Regulated Service) for determining the position of emergency vehicles under real-life conditions in a complex urban environment. Based on this position determination, a preemption is given to emergency vehicles at traffic lights to cross safely and to...
Article
Full-text available
The performance of global navigation satellite system (GNSS) receivers is significantly affected by interference signals. For this reason, several research groups have proposed methods to mitigate the effect of different kinds of jammers. One effective method for wide-band interference mitigation (IM) is the high-rate DFT-based data manipulator (HD...
Article
Full-text available
Proper signal conditioning is crucial for reliable Global Navigation Satellite System (GNSS) navigation. Signal conditioning includes correcting receiver front‐end distortions, shaping noise, removing interferences, and altering the received signal. The high‐rate DFT‐based data manipulator (HDDM) is a versatile signal processing architecture based...
Patent
An apparatus for obtaining a weighting matrix, the weighting matrix to be used to obtain one or more updated parameters affecting a time of response of a tracking loop; wherein the apparatus is configured to receive from a plurality of tracking loops respective loop dynamic estimates and/or loop noise estimates, weight each of the received loop dyn...
Article
Full-text available
GNSS receivers use tracking loops to lock onto GNSS signals. Fixed loop settings limit the tracking performance against noise, receiver dynamics, and the current scenario. Adaptive tracking loops adjust these settings to achieve optimal performance for a given scenario. This paper evaluates the performance and complexity of state-of-the-art adaptiv...
Article
Full-text available
Interference can significantly degrade the performance of global navigation satellite system (GNSS) receivers. Therefore, mitigation methods are required to ensure reliable operations. However, as there are different types of interference, robust, multi-purpose mitigation algorithms are needed. This paper describes the most popular state-of-the-art...
Patent
A receiver comprises an analog beamforming and nullsteering network connected to one or more antennas from receiving RF signals and configured to preprocess the RF signals in order to mitigate interferences within the RF signals; and a digital stage connected to the analog beamforming and nullsteering network and configured to further process the p...
Conference Paper
Full-text available
Global navigation satellite system (GNSS) receivers require a substantially large bandwidth to be able to use all available GNSS signals in the L1 frequency band (i.e. GPS, Galileo, BeiDou and GLONASS). Consequently, high throughput, processing, and storage requirements exist. It is especially problematic for software-defined radio (SDR) receivers,...
Conference Paper
Full-text available
Spoofing, the transmission of false global navigation satellite system (GNSS) signals, is a problem for a GNSS receiver. Therefore , a spoofing attack should be detected by a receiver to ensure the integrity of the position, velocity, and time (PVT) solution. Detecting an attack is more difficult for a snapshot receiver, as temporal changes cannot...
Patent
An apparatus for generating a reconstructed time-domain signal from an input time-domain signal is provided. The apparatus comprises a transformation unit (110), a manipulation unit (120), and a reconstruction unit (130). In a first clock cycle, the transformation unit (110) is configured to transform a first plurality of time-domain samples of the...
Conference Paper
Full-text available
Global navigation satellite system (GNSS) transmit signals with code-division multiple access (CDMA) sequences. A receiver should know these sequences such that the signal can be extracted and used for positioning, navigation, and timing (PNT). This paper presents a system which estimates these sequences in a way that they could be used without pri...
Conference Paper
Full-text available
Interferences can significantly degrade the performance of global navigation satellite system (GNSS) receivers. Therefore, mitigation methods are required to ensure reliable operations. However, as there are different types of interferences, robust, multi-purpose mitigation algorithms are needed. The high-rate DFT-based data manipulator (HDDM) algo...
Conference Paper
Full-text available
This paper presents a concept for a pseudolite navigation system that also allows spectral denial. The system denies global navigation satellite system (GNSS) signals to any unwanted receivers while maintaining navigation capability for desired ones, with required modifications. The interference impact on GNSS signals is evaluated, as these are req...
Conference Paper
Full-text available
Sensitivity-analysis of a global navigation satellite system (GNSS) receiver presents the limit of operation for a given scenario. It allows us to characterize its performance in harsh conditions and to sets design constraints. This paper presents a model for the full system sensitivity for a GNSS snapshot-based receiver. The probability of a succe...
Conference Paper
Full-text available
This paper analyzes the performance and complexity of state-of-the-art adaptive scalar tracking techniques used in modern digital global navigation satellite system (GNSS) receivers. Ideally, a tracking channel should be able to adjust to both noisy and dynamic environments for optimal performance. Precision and robustness define the performance of...
Conference Paper
Full-text available
This paper presents a loop-bandwidth control algorithm for adaptive scalar tracking loops used in modern digital global navigation satellite system (GNSS) receivers. This algorithm modifies the noise bandwidth of the loop filter. The updated loop-bandwidth balances the signal dynamics and noise through a weighting function. The agility of the estim...
Article
Full-text available
Spoofing of global navigation satellite system (GNSS) signals threatens positioning systems. A counter-method is to detect the presence of spoofed signals, followed by a warning to the user. In this paper, a multi-antenna snapshot receiver is presented to detect the presence of a spoofing attack. The spatial similarities of the array steering vecto...
Conference Paper
Full-text available
Privacy protection devices (PPDs) are cheap and freely available global navigation satellite system (GNSS) jammers which interfere with GNSS receivers. This causes major disruption, and therefore these interferences should be mitigated by receivers. Adaptive notch filtering (ANF) is an effective interference mitigation method against PPDs, as these...
Conference Paper
Full-text available
Cooperative spoofing attacks are difficult to detect and to mitigate. In these attacks the user or owner of the global navigation satellite system (GNSS) receiver is also the attacker, hence, he can ensure ideal spoofing circumstances. Such attacks are associated with criminal activities where the user wants to falsify his own position. A low-cost...
Conference Paper
Full-text available
A global navigation satellite system (GNSS) snapshot receiver records a snapshot of raw data and then forwards it to a server for processing. The server then sends information regarding the position and time for the receiver back to the receiver. This technology enables low-power positioning and can also be used for remote processing of encrypted s...
Conference Paper
Die Steuerung von Lichtsignalanlagen (LSA) hat einen wichtigen Einfluss auf die Qualität, die Sicherheit und die Umweltverträglichkeit des Verkehrsablaufs in städtischen Straßennetzen. Zu diesem Zweck kommen verschiedene Steuerungsansätze [1], [2] und Systeme zur Anwendung, die z.B. auch die Bevorrechtigung der Sondereinsatzfahrzeuge (SEF) von Poli...
Conference Paper
Das Ziel des Forschungsprojektes "HALI Berlin" ist es eine Einsatzwagenbevorrechtigung entlang dynamischer LSA-Routen auf Basis des Europäischen Satellitennavigationssystems Galileo und des PRS-Dienstes (Public Regulated Service) unter den realen Bedingungen eines komplexen, innerstädtischen Testfeldes zu demonstrieren. Dieser Beitrag gibt einen Ei...
Conference Paper
Full-text available
In this paper, we present a practical implementation and evaluation of the open service navigation message authentication (OS-NMA) scheme proposed for Galileo. A file-system based solution is used to parse the results, making this implementation receiver independent. Therefore, extending to current commercial receivers to support OS-NMA, without ad...
Conference Paper
Full-text available
All spoofer attacks have different requirements, impacts, success rates and objectives; therefore, to assess the threat and to develop appropriate counter measures, a clear classification is needed. Being aware of the different existing types of threats, allows an improved design of preventative measures to counter these attacks. This paper classif...
Patent
A navigation receiver for determining a position, wherein the navigation receiver is configured to determine a position on the basis of a global navigation satellite system signal, wherein the navigation receiver is configured to recognize a presence of one or more jamming signals overlaying the global navigation satellite system signal or lying wi...
Conference Paper
Full-text available
This paper analyzes the signals of different commercial-off-the-shelf (COTS) privacy protection devices (PPDs), and compares several mitigation algorithms applied to these jamming signals. A review of the mitigation algorithms is presented, including the theoretical requirements. This paper allows an end-to-end comparison of the algorithms in terms...
Article
Antenna characterisation is usually performed by antenna pattern measurements in an anechoic chamber. Subsequently, a conducted test, the radiated two-stage or the wireless-cable method can be used for an overall system evaluation considering the measured patterns. In this study, the authors present a method to perform device tests for antenna arra...
Conference Paper
In this paper a filter bank pulse blanking (FBPB) approach is presented as a wide-band (WB) mitigation method for chirp-like interferences. This method uses a filter bank to separate the received global navigation satellite system (GNSS) signal in different sub-bands. As the WB chirp is broken into several segments, standard time domain pulse blank...
Conference Paper
In this paper, we present a versatile, configurable and customizable GNSS interference detection station. Up to three GNSS bands with a bandwidth of up to 80 MHz and a resolution of up to 8 bit can be continuously analyzed. If an interference is found, a user customizable signal characterization is carried out to extract the interference signal’s p...