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Near Vertical Incidence Skywave communication solutions are known to be reliable and quickly deployable, but modeling a suitable radio link requires a good prediction of the ionosphere behavior and insights regarding ionospheric propagation. Within the framework of the national PN-II SIRIUS project, the Technical University of Cluj-Napoca has acquired, installed, and employed the NovAtel GPStation-6...
Ionospheric scintillation monitoring is becoming an increasing research activity in order to devise countermeasures to the harmful effects ionospheric activity has on positioning services based on Global Navigation Satellite Systems (GNSS). The amount of amplitude fluctuations in GNSS signals due to scintillation is estimated by the �������� index. For this purpose, traditional closed loop architectures...
This paper presents the latest development of NSSC's integrated GNSS remote sensing instrument. This new instrument is flexible designed for a variety of GNSS science needs based on the successful GNOS receiver, but with more functional modules. The goal of this instrument is to be put onboard of future Chinese space-borne platforms to provide precise position and timing information for high-demand...
Due to a rapid development of several Global Navigation Satellite Systems (GNSS), multiple constellations are available to enhance navigation performance and safety. With the growing number of satellite constellations, the task of the GNSS navigation is to deal with the differences among systems but, on the other hand, more great levels of integrity and satellite visibility can be expected. GNSS navigation...
In recent years GNSS has become the recognised core element for the provision of accurate and reliable positioning, velocity and timing (PVT) data for multiple navigational applications. However, since the occurrence of strong ionospheric disturbances impacts the accuracy of GNSS measurements leading consequently to unreliable PVT solutions, not only precision and accuracy but also high-level reliability...
Many GNSS (Global Navigation Satellites System) applications need high integrity performances. Receiver Autonomous Integrity Monitoring (RAIM), or similar method, is commonly used. Initially developed for aeronautics, RAIM techniques may not be fully adapted for terrestrial navigation, especially in urban environments. Those techniques use basically the pseudoranges to derive an integrity criterion...
Ionospheric scintillation monitoring is becoming an increasing research activity in order to devise countermeasures to the harmful effects ionospheric activity has on positioning services based on Global Navigation Satellite Systems (GNSS). The amount of amplitude fluctuations in GNSS signals due to scintillation is estimated by the �������� index. For this purpose, traditional closed loop architectures...
Numerous works have investigated the vulnerability of Global Navigation Satellite Systems (GNSS) against attacks. Upcoming systems make provisions for cryptographic civilian signal protection. However, this alone does not fully protect GNSS-based localization. In this paper, we show that attacks at the physical layer, without modification of navigation messages, can be severely effective. We analyze...
Ionospheric propagation is harmful for the electromagnetic signals broadcast by Global Navigation Satellite System (GNSS) satellites, mainly because of the presence of electron density anomalies. GNSS receivers are indeed of primary importance in scintillation and Total Electron Content (TEC) monitoring, especially at low and high latitudes, where scintillations are more frequent. Professional dual...
GNSS System time offset between two satellite navigation systems is one of the most important aspects of their interoperability and compatibility. This paper introduces the research work of GNSS System Time Offset Monitoring at NTSC. The method of GNSS System Time Offset monitoring by Signal-in-Space Reception is described. Multi-GNSS receiver calibration is the key technology of GNSS system time...
This paper presents the features of the MONITOR project. This project initiated by ESA / ESTEC aims to increase the knowledge of the ionospheric effects and its impact on GNSS systems during active periods of solar activity. It includes the deployment of a set of GNSS-based ionospheric monitoring receivers worldwide distributed, the development of specific analysis software tools some of them integrated...
This article describes a GNSS monitoring station over the L band. The monitoring is performed in two different ways: over the signal's spectrum by means of statistical analysis and in the range domain determining the horizontal protection level. The horizontal protection level ensures that the user's location is within a certain range with a certain probability and is used as input in decision making...
The ionosphere, if not modeled sufficiently well, is the largest contributor of error in single frequency GNSS receivers. Modeling ionospheric effects is a major concern for a number of GNSS applications. Ionospheric disturbances induce rapid fluctuations in the phase and the amplitude of received GNSS signals. These rapid fluctuations or scintillation potentially introduce cycle slips, degrade range...
Spoofing and jamming in the form of transmitting counterfeit location information and denying services are an emerging threat to GNSS receivers. In general, spoofing is a deliberate attack that aims to coerce GNSS receivers into generating false navigation solutions. The spoofing attack is potentially more hazardous than jamming since the target receiver is not aware of this threat and it is still...
Integrity monitoring is considered now as an important part of a vehicle navigation system. Localisation sensors faults due to systematic malfunctioning require integrity reinforcement of multi-sensors fusion method through systematic analysis and reconfiguration method in order to exclude the erroneous information from the fusion procedure. In this paper, we propose a method to detect faults of the...
Services based on Global Navigation Satellite Systems (GNSS) are currently in use in many critical networked infrastructures and crucial applications. Within the described scenario, the importance for the GNSS community of investigating the effects of spoofing attacks, together with anti-spoofing techniques, appears essential. This paper describes the results of preliminary tests performed in lab...
The provision of robust position, navigation and timing (PNT) information is a fundamental element of the e-Navigation initiative proposed by the International Maritime Organization (IMO). In this context the single Electronic Position Fixing System (EPFS), which currently conforms to the minimum carriage requirement, should be replaced by an integrated PNT unit as future onboard integrated system...
In order to meet the demands of complicated calculation and high real-time performance, a new implementation of multi-mode GNSS signal simulator controlled by computer is proposed. Navigation control parameters are calculated by computers. Then, they are sent to satellite signal generator via network interface to control signal generation. This combination displays strong advantages of parallel processing...
The paper deals with the real-time monitoring of the European Geostationary Navigation Overlay Service (EGNOS). Possible approaches to the monitoring are discussed at first. The rest of the paper presents the development of C++ software for real-time monitoring of EGNOS performance in the position domain. The software is intended to be used within the GNSS monitoring station run by the Department...
QZSS (quasi-zenith satellite system) is a Japanese satellite navigation program offering GPS augmentation signal, called L1-SAIF (submeter-class augmentation with integrity function), on the GPS L1 frequency. L1-SAIF augmentation will improve user position accuracy within 1 meter RMS nationwide based on wide-area differential GPS technique and provide users with the integrity information necessary...
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