Impact of Pseudolite Signals on Non-Participating GPS Receivers

Pseudolites or pseudo-satellites are an emerging technology that has the potential to extend the capability of Global Navigation Satellite Systems (GNSS) indoors and in harsh environments where GNSS services are denied. Although their potential, pseudolites could cause severe interference problems to non-participating receivers, i.e., GNSS receivers unable or not designed to use pseudolite signals. In this report, preliminary results obtained by the IPSC-JRC on the impact of pseudolite signals on commercial non-participating receivers are presented. The analysis considered two pseudolite modulations. In the fist case, the pseudolite signal has same structure adopted by GPS L1 C/A signals whereas in the second scenario a pulsing scheme has been adopted to reduce the interference problem. From the analysis, it emerges that in the case of a continuous pseudolite modulation, the performance of the non-participating receiver is already significantly degraded when the pseudolite signal is about 10 times stronger than the average signal power. More specifically, a 3 dB loss is introduced in the estimated C/N0 of the useful GPS signals. The use of a pulsing scheme significantly mitigates the impact of pseudolite signals and the receiver is able to maintain lock and provide a position solution for all the tested pseudolite power levels. Further investigations are required to determine if higher pseudolite signal powers could affect more severely a non-participating receiver.JRC.DG.G.6-Security technology assessmen

Radio Frequency Interference Impact Assessment on Global Navigation Satellite Systems

The Institute for the Protection and Security of the Citizen of the EC Joint Research Centre (IPSC-JRC) has been mandated to perform a study on the Radio Frequency (RF) threat against telecommunications and ICT control systems. This study is divided into two parts. The rst part concerns the assessment of high energy radio frequency (HERF) threats, where the focus is on the generation of electromagnetic pulses (EMP), the development of corresponding devices and the possible impact on ICT and power distribution systems. The second part of the study concerns radio frequency interference (RFI) with regard to global navigation satellite systems (GNSS). This document contributes to the second part and contains a detailed literature study disclosing the weaknesses of GNSS systems. Whereas the HERF analysis only concerns intentional interference issues, this study on GNSS also takes into account unintentional interference, enlarging the spectrum of plausible interference scenarios.JRC.DG.G.6-Security technology assessmen

Optimization Techniques for MIMO Radar Antenna Systems

Topology Optimization Technique is a new technique to obtain optimum topologies for MIMO antenna array systems. The target of the optimization is the identification of the optimal arrangement of the transmitters and receivers giving the highest detection performance to obtain radar images as similar as possible to those obtained in SAR techniques. To carry out this task we focused on the concept of the phase center.JRC.G.6-Sensors, radar technologies and cybersecurit

Radar Cross Section Measurements of Pedestrian Dummies and Humans in the 24/77 GHz Frequency Bands

Road safety has become a major societal issue that should not be ignored. At present, a wide range of new technologies, including intelligent speed adaptation and collision avoidance systems, are being introduced to improve road safety levels and reduce these casualties. Among the various types of collision avoidance systems, automotive short-range radars (SRRs) are those most widely deployed. A recent Communication of the European Commission (i.e., SEC(2010) 903) has stated that a wide deployment of SRR systems could help to reach the EU’s policy goal of halving the number of deaths on the road. In this context, it is very important to make sure that the SRR signatures of pedestrian dummies match those of humans with a high degree of accuracy. This report summarizes the results of an extensive series of radar cross section (RCS) laboratory measurements on pedestrian dummies and humans completed in August 2012 at the European Microwave Signature Laboratory of the EC Joint Research Centre. This measurement campaign has allowed the establishment of a reference library with the RCS signatures of pedestrian dummies and humans in the 24 GHz and 77 GHz bands, which are those currently allocated for automotive SRR systems. Results show for the first time that the observed global frequency/azimuth RCS averages in the two frequency bands are very close to each other. A significant impact of the pedestrian height on the observed RCS, particularly at 77 GHz, has also been noted. A first qualitative comparison of the RCS signatures between dummies and humans was also completed. and showed that the RCS averages of the available dummies are slightly below those of the humans. Finally, following a dedicated series of measurements, it has been observed that the impact of the clothing on the measured signatures is minimal except for those cases where some very thick clothes were worn.JRC.G.6-Security technology assessmen

Scoping Study on Pseudolites

Pseudolites or pseudo-satellites are an emerging technology with the potential of enabling satellite navigation indoors. This technology found several applications that are not limited to indoor navigation. Precise landing, emergency services in difficult environments and precise positioning and machine control are few examples where pseudolite technology can be employed. Despite the great potential of this technology, severe interference problems with existing GNSS services can arise. The problem can be particularly severe when considering non-participating receivers, i.e., legacy devices not designed for pseudolite signals. The design of pseudolite signals is thus a complex problem that has to account for market requirements (modifications of existing receivers for enabling the use of pseudolite signals, measurement accuracy, target application), regulatory aspects (frequency bands to be allocated for pseudoliteservices) and interference problems. The main aspects for the design of a pseudolite signal standard minimizing the interference problem without compromising the location capabilities of the system are considered. The focus is on the signal characteristics and topics relevant for the signal design. A literature review on the different pseudolite applications, prototypes and solutions adopted for minimizing the interference problem is first conducted. Recommendations on the aspects that should be further investigated are then provided.JRC.DG.G.6-Security technology assessmen

Exploring the Limits of Multi-Antenna Signal-Rejection for GNSS Receivers

This paper presents experimental results exploring the performance of GNSS receivers equipped with controlled radiation pattern antennas. Experiments focus on identifying those features and characteristics of their implementation that may limit the achievable performance of signal-rejection techniques. The study describes both conductive and broadcast experiments conducted in a large anechoic chamber and computer-based Monte-Carlo simulations. Results include a precise gain pattern measurement of a typical antenna array, an investigation and comparison of both analogue RF and digital IF null steering along with some novel theoretical results.JRC.G.5-Security technology assessmen

Interference from Low-Duty Cycle 26 GHz Automotive Short Range Radar (SRR)

Currently, there are two frequency bands allocated to Ultra-Wideband (UWB) automotive short range radar (SRR) equipment in Europe. In its Decision 2005/50/EC of 17 January 2005 [1] the European Commission (EC) designated the frequency band 21.65-26.65 GHz (referred to as the “24 GHz band”) for use until mid 2013. The frequency band 77-81 GHz (the “79 GHz band”) has been designated and made available for permanent usage by EC Decision 2004/545/EC of 8 July 2004 [2] In order to ease the transition from 24 GHz to 79 GHz technology the EC considers authorizing the use of a band in the 24 GHz range for SRR beyond 2013. In Report 37 of the European Conference of Postal and Telecommunications Administrations (CEPT) [3] which was prepared in response to the “SRR mandate 2” issued by the EC to the CEPT it is proposed to allocate the frequency band 24.25 – 27.50 GHz (the “26 GHz band”) to SRR and reduce the risk of interference to licensed services operating in the same band through lower transmit power limits and low duty cycle (LDC) operation. As this proposal was not accepted the discussion now centres on the frequency band 24.25 – 26.65 GHz (the “revised 26 GHz band”). The objective of this report is to complement the very detailed and comprehensive compatibility studies that have been undertaken by CEPT, ITU-R, ETSI, and other institutions over the past years by evaluating the impact of LDC on the level of interference generated by automotive UWB SRR systems in the revised 26 GHz band. In particular, the impact on digitally modulated single carrier signals as used by licensed microwave fixed wireless links is investigated. The conclusions drawn in this report will hopefully be useful for defining the future regulation for automotive SRR in the European Union.JRC.DG.G.6-Security technology assessmen

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Impact Study of Unintentional Interference on GNSS Receivers

This work has been performed in the context of an Administrative Arrangement for DG HOME. The overall scope is to perform an impact assessment of radio frequency (RF) interference on critical infrastructures relying on GNSS-services for timing and synchronization purposes. In WP3, the analysis has been divided into the impact of intentional interference on critical infrastructures presented in WP3.1 and the analysis of unintentional interference, covered in this report. DVB-T has been identied as the most important source of unintentional interference in the GNSS frequency bands and therefore a special attention is paid to this interference source. The main motivation to assess the performance reduction of receivers due to unintentional interference, is related to the high probability of these events. Unintentional interference stems from out-of-band emissions or spurious transmissions. Four different scenarios have been considered in this work, covering (i) additive white Gaussian noise, (ii) continuous wave interference, (iii) pulsed continuous wave nterference and (iv) interference that stems from the third harmonic of DVB-T transmissions. All these scenarios are highly relevant and are frequently observed in realistic signal conditions. The scenario of DVB-T interference receives most of the attention in this work, since DVB-T has become the most widely adopted digital terrestrial television broadcasting standard in the world. Harmonics of the DVB-T signal could possibly fall together with the GPS L1 or Galileo E1 bands and as such become a threat. DVB-T services are operational in more than 40 countries, with more than 75% of the deployment in Europe. In the coming years, DVB-T is expected to be deployed in more than 100 countries. In the frame of this work, different tools have been developed to quantify the impact of unintentional interference. First, a laboratory testbed has been set up, that allows to take real GPS L1 signals, combine them with synthetic interfering signals and test the robustness of different commercial and professional receivers. Further, in order to have a full control of the signal characteristics and the implementation details of the receiver, a simulation platform has been developed. This simulation tool generates GNSS as well as interfering signals, and observes consequently the impact on the acquisition or tracking performance for different receiver implementations. Finally, since it is difcult to reach statistical signicance for the acquisition performance, an analytical tool has been developed allowing to evaluate the effects of interference. This report summarises the relevant results for the four considered scenarios. For the assessment of the acquisition performance the analytical tool and the simulation platform have been used. In order to evaluate the tracking performance, experimental work has been conducted with real receivers and simulations have been performed. For the acquisition, the report quanties how much the probability of detection and the probability of false alarm are affected by the presence of interference. For the tracking, the main result of this report is the quantication of the signal degradation in terms of C=N0 and in terms of the variance of the position solution. In the scenario of DVB-T Page 2 of 94 WP3.2 interference, the degradation of the signal quality has been determined as a function of the DVB-T third harmonic power and the distance between the victim receiver and the DVB-T base station.JRC.DG.G.6-Security technology assessmen

A Galileo IOV Assessment: Measurement and Position Domain

The European GNSS, Galileo, is currently in its In-Orbit Validation (IOV) phase where four satellites are finally available for computing the user position. In this phase, the analysis of the measurements and Position Velocity and Time (PVT) obtained from the IOV satellites can provide insight on the potentialities of the Galileo system. A methodology is suggested for the analysis of the Galileo IOV pseudorange and pseudorange rates collected from the E1 and E5 frequencies. Several days of data were collected and processed to determine figures of merits such as RMS and maximum errors of the Galileo observables. From the analysis, it emerges that Galileo is able to achieve better accuracy with respect to GPS. A thorough analysis of the PVT performance is also achieved using broadcast ephemerides. Galileo and GPS PVTs are compared under similar geometry conditions showing the potential of the Galileo system.JRC.G.5-Security technology assessmen