104 research outputs found

    The COST 271 Action: conclusions and the way ahead

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    A brief summary is given of the major achievements of the COST 271 Action. New challenges have been identified that open the way for a proposal, which is outlined, for a follow-on to the COST 271 Action within the COST Telecommunications, Information Science and Technology framework

    COST 271 Action - Effects of the upper atmosphere on terrestrial and Earth-space communications: introduction

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    The COST 271 Action («Effects of the Upper Atmosphere on Terrestrial and Earth-space Communications ») within the European ionospheric community has the objectives, embodied in the Memorandum of Understanding (MoU): to study the influence of upper atmospheric conditions on terrestrial and Earth-space communications, to develop methods and techniques to improve ionospheric models over Europe for telecommunication and navigation applications and to transfer the results to the appropriate Radiocommunication Study Groups of the International Telecommunication Union (ITU-R) and other national and international organizations dealing with the modern communication systems. This introductory paper summarises briefly the background and historical context of COST 271 and outlines the main objectives, working methods and structure. It also lists the participating countries and institutions, the Management Committee (MC) Meetings, Workshops and Short-term Scientific Missions. In addition, the paper discusses the dissemination of the results and the collaboration among the participating institutions and researchers, before outlining the content of the Final Report

    The European COST (Co-operation in the field of Scientific and Technical Research) Actions: an important chance to cooperate and to grow for all the international ionospheric community

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    The current COST (Co-operation in the field of Scientific and Technical Research) Action 296 on Mitigation of Ionospheric Effects on Radio Systems, along with previous COST238 (Prediction and Retrospective Ionospheric Modelling over Europe), COST251 (Improved Quality of Service in Ionospheric Telecommunication Systems Planning and Operation) and COST271 (Effects of the Upper Atmosphere on Terrestrial and Earth-Space Communications) Actions have addressed investigations of the different effects of the ionosphere on terrestrial telecommunication systems and on Earth-space systems. Throughout their lifetime of 20 years, these COST actions have achieved a great deal in long-term archiving of synoptic soundings of the state of the ionosphere, in enhancing understanding of the morphology of the ionosphere and its dependence on space weather and in producing ionosphere-plasmasphere as well as propagation models for terrestrial radio services available to variety of radio users. Besides the formal contributions to ITU-R and the contributions to international organisations such as URSI, COSPAR, EGU and ESA, these COST Actions have provided a forum for the establishment of collaborative European initiatives, a centre of expertise and excellence in ionosphere knowledge when none other equivalent in Europe or elsewhere exists. In this paper, we review the main achievements of the COST 238, 251 and 271 actions as developed in the past studies

    Regional GPS receiver networks for monitoring local mid-latitude total electron content

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    Two regional GPS receiver networks from the Ordnance Survey U.K.(OS)and the Italian Space Agency (ASI) have been used for monitoring mid-latitude Total Electron Content (TEC)during quiet and disturbed ionospheric conditions in the current solar cycle.A few quiet and disturbed days in March and April 2002 were examined. These showed how the temporal and spatial patterns of changes develop and how they are related to solar and geomagnetic activity for parameter descriptive of plasmaspheric-ionospheric ionisation.Use is then made of computer contouring techniques to produce snapshots of daily maps of TEC for these different regional areas

    Proposed terminology for the classification and parameters for the quantification of variability in ionosphere morphology

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    Much uncertainty currently exists in the use by different workers of the term ‘variability’ in describing the results of statistical analyses applied to ionospheric measurement data sets and in their relationships with various existing or new ionospheric models. Often it is not clear whether data for different time periods or different geographical areas, and if so which, are being used to formulate results. Terms are presented in the Annex which it is suggested should be used, at least once in every publication addressing this topic, to describe unambiguously what is talked about. The background to the proposed terminology is discussed. Options for variability parameters are also addressed

    COST 296 MIERS: Mitigation of Ionospheric Effects on Radio Systems

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    The COST 296 Action MIERS (Mitigation of Ionospheric Effects on Radio Systems) within the ionospheric community has the objectives, embodied in the Memorandum of Understanding (MoU), to develop an increased knowledge of the effects imposed by the ionosphere on practical radio systems, and the development and implementation of techniques to mitigate the deleterious effects of the ionosphere on such systems. This introductory paper summarizes briefly the background and historical context of COST 296 and outlines the main objectives, working methods and structure. It also lists the participating countries and institutions, the Management Committee (MC) Meetings, the Workshops, Short-term Scientific Missions. In addition, the paper discusses the dissemination activities and the collaboration among the participating institutions and researchers, before outlining the content of the Final Report

    Ionospheric storm forecasting technique by artificial neural network

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    In this work we further refine and improve the neural network based ionospheric characteristic's foF2 predictor, which is actually a neural network autoregressive model with additional input signals (NNARX). Our analysis is focused on choice of X parts of NNARX model in order to capture middle and long term dependencies. Daily distribution of prediction error suggests need for structural changes of the neural network model, as well as adaptation of running average lengths used for determination of X inputs. Generalisation properties of proposed neural predictor are improved by carefully designed pruning procedure with additional regularisation term in criterion function. Some results from the NNARX model are presented to illustrate the feasibility of using such a model as ionospheric storm forecasting technique

    Monitoring and Forecasting the Ionosphere Over Europe: The DIAS Project

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    Knowledge of the state of the upper atmosphere, and in particular its ionospheric part, is very important in several applications affected by space weather, especially the communications and navigation systems that rely on radio transmission. To better classify the ionosphere and forecast its disturbances over Europe, a data collection endeavour called the European Digital Upper Atmosphere Server (DIAS) was initiated in 2004 by a consortium formed around several European ionospheric stations that transmit in real-time ionospheric parameters automatically scaled. The DIAS project is a collaborative venture of eight institutions funded by the European Commission eContent Programme. The project seeks to improve access to digital information collected by public European institutes and to expand its use. The main objective of the DIAS project is to develop a pan-European digital data collection describing the state of the upper atmosphere, based on real-time information and historical data collections provided by most of the operating ionospheric stations in Europe. Various groups of users require data specifying upper atmospheric conditions over Europe for nowcasting and forecasting purposes. The DIAS system is designed to distribute such information. The successful operation of DIAS is based on the effective use of observational data in operational applications through the development of new added-value ionospheric products and services that best fit the needs of the market. DIAS is a unique European system, and its continuous operation will efficiently support radio propagation services with the most reliable information. DIAS began providing services to users in August 2006
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