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The ionosphere behaviour over Mexico was studied. We analysed variations of Total Electron Content (TEC) and critical frequency of F2-layer of the ionosphere (foF2). TEC values were extracted from data of local GNSS receivers and if missed then from global ionospheric maps. foF2 values were reconstructed using TEC measured over Mexico and equivalent slab thickness of the ionosphere measured in the...
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...
Ionospheric irregularities if persisted may lead to change in phase and amplitude of satellite signals and hence, ionospheric scintillation. Strong scintillation may induce loss of signal, cycle slips or excessive phase noise. The errors incurred by the radio signals could be disastrous especially to very sensitive agencies that make use of it if not properly managed. It is therefore pertinent to...
This paper addresses the design and implementation of an Ionospheric Scintillation Monitoring Receiver based on the Software Defined Radio paradigm. The monitoring platform exploits a digital data grabber and a GNSS fully software receiver, which grants a high level of flexibility for the processing strategy and the storage of raw samples of the signals in case of meaningful scintillation events....
This study compares and analyzes phase scintillation σφ during periods of low and high solar activity. This study focused on the low solar activity from July 2007 to June 2008 (sunspot number (SSN) ranging from 0 to 10) and the high solar activity from July 2013 to June 2014 (SSN 37-103). The data were obtained from a GISTM receiver at the Wireless and Radio Science Centre, Universiti Tun Hussein...
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...
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...
Perspective method for the monitoring and on-line modulation analysis in the HF band is presented in this paper. The workplace for the on-line analysis of analog and digital modulations consists from the digital receiver IZ225 and a PC with adequate SW. The original program for the on-line modulation signal analysis was designed in the programming environment CipherCAD. The type of modulation, its...
This work investigates the occurrence of radiowave propagation disturbances across a wide range of VLF and LF frequencies received prior to a seismic event (Mw=4), that took place on May 12th 2012, the epicenter of which was very close (14Km) to the receiver. The signals analysed were from 4 VLF and 6 LF European transmitters. This seismic event produced precursory ionospheric disturbances, identified...
The recent proliferation of multi-constellation Global Navigation Satellite Systems (GNSS) is offering a great opportunity for ionosphere scintillation studies. Since 2009, our research team has established permanent and temporary portable ionosphere scintillation monitoring and data collection systems in Alaska, Ascension Island, Hong Kong, Peru, and Singapore to collect multi-constellation multi-frequency...
This paper presents a novel ionospheric anomaly monitoring method for ground-based augmentation systems, based on a network of collaborative airborne dual-frequency receivers. The method allows aircraft to navigate safely using a single frequency or divergence-free position solution, methods that are more accurate than the ionosphere-free position solution. Each receiver measures ionospheric delays;...
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...
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...
The Antarctic-Arctic Radiation-belt (Dynamic) Deposition — VLF Atmospheric Research Konsortium (AARDDVARK) provides a network of continuous long-range observations of the lower-ionosphere in the polar regions. The network of sensors detect changes in ionisation levels from ∼30–90 km altitude, globally, continuously, and with high time resolution, with the goal of increasing the understanding of energy...
We report here preliminary observations of phase and amplitude perturbations in VLF signal propagating in the Earth-ionosphere waveguide, monitored at low latitude station Varanasi using SoftPAL Receiver. Phase and amplitude perturbations (trimpis) on VLF signals consists of a sudden change in phase and amplitude of the transmitter signal followed by a slow recovery to the initial levels as the ionization...
Strong scintillations over Pontianak (0.2°N 109.20°E, geomagnetic latitude is 6.09°N), and over Bandung (6.5°S 107.3°E, geomagnetic latitude is 16.5°S) was compared to find out the spatial distribution of ionospheric scintillation. Data was obtained from GISTM GSV4004B. Percentage occurrence of strong scintillation was counted at each observation station. Result showed the occurrence of scintillation...
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