THIRD TRANSMIT SUMMER SCHOOL

Transcription

1 THIRD TRANSMIT SUMMER SCHOOL 1-5 July (Monday-Friday) 2013 Istituto Nazionale di Geofisica e Vulcanologia Via Di Vigna Murata Rome Italy Ionospheric threats to Europe: impact of increased solar activity TRAINING RESEARCH AND APPLICATION NETWORK TO SUPPORT THE MITIGATION OF IONOSPHERIC THREATS TRAINING RESEARCH AND APPLICATION NETWORK 1 st July Geomagnetism at Istituto Nazionale di Geofisica e Vulcanologia Antonio Meloni, Istituto Nazionale di Geofisica e Vulcanologia, Italy For a long time the understanding of magnetism and terrestrial magnetism, has grown on equal footsteps, being the Earth s magnetic field a natural gigantic laboratory for magnetism. Subsequently Geomagnetism has developed as an independent discipline and has always been at the forefront among the various branches of geophysics and space physics. In this presentation some of the fundamentals of Geomagnetism: the earth s magnetic field, magnetic space time variations and anomalies, and some elements of the complex aspects of the field generation processes, will be presented. The focus will then be on activities, like observations and data service, that have been carried out at INGV in this field, including contributions to space weather, in which Geomagnetism plays a special role. INGV, in fact, has been traditionally active in Geomagnetism and in particular in monitoring and studying the effects of solar perturbations on the Earth s magnetic field. From Guglielmo Marconi To nowadays: a long tradition of ionospheric measurements at Istituto Nazionale di Geofisica e Vulcanologia Bruno Zolesi, Istituto Nazionale di Geofisica e Vulcanologia, Italy Guglielmo Marconi, Nobel prize in 1909 for his contribution to the development of wireless telegraphy, realizing on 12th December 1901 a transoceanic radio link, was the first to provide the experimental proof of the existence of the Ionosphere, postulated during the eighteenth century by various scientists like Balfour Stewart and Arthur Schuster. In 1936 he was the founder of the former Istituto Nazionale di Geofisica, a government institution with the main mission of the monitoring of geophysical phenomena in both the solid and fluid components of the Earth, promoting there the initial studies of radio propagation. After the first experiments performed in 1938 a prototype of a homemade ionosonde was built by the ionospheric group of ING in Then the years after the second world war to the international geophysical year were characterized by the need to organize an ionospheric observatory in Rome to provide a continuous and systematic monitoring of the in ionospheric characteristics according the URSI specifications. A short history of the ionospheric studies at INGV that followed the evolution of the ionospheric vertical sounding are here shortly reported. Since the first archeo ionosondes Union Radio and Bibl Panorama used during 50 and 60 years to define the morphology and the normal ionosphere over Rome to the development of the digisondes, the 128P and 256 in 70 and 80 years and the recent and modern DPS4 in the last decades. Finally the automatic scaling methods applied to the digisondes and to the homemade AIS ionosonde able to provide now casting picture of the ionosphere over the station. Cosmic radio noise as well as ionospheric scintillation measurements for satellite navigation application complete during the new millennium the panorama of the ionospheric research performed by the ionospheric group at INGV. graphic design by Laboratorio Grafica & Immagini INGV

2 2 nd July Total Electron Content Variability in Europe Ljiljana R. Cander, Rutherford Appleton Laboratory, United Kingdom Over the last two decades our understanding and appreciation of the Earth s upper atmosphere have changed dramatically with the realization that thousands of ground-based dual frequency GPS receivers measure ionospheric total electron content (TEC) continuously in multiple directions. With near real-time nature of these measurements, a unique data stream exists from which both spatial and temporal variability as a permanent ionospheric feature can be successfully studied. Quantifying the variability, defined as the deviation from climatological mean that occurs on hourly, daily, seasonally, and solar cycle timescales, and exploring its association with solar-terrestrial conditions and meteorological processes is a topic of great importance for variety of GNSS applications as well as for scientific purposes. Rather than giving huge review of the undoubted research progress that has been made so far, the paper presents an attempt to identify some key issues within the topic; consider the current status of the topic, and offer some ideas on future research directions. Ionospheric Scintillation Models Andrzej W. Wernik, Space Research Center, Polish Academy of Sciences, Poland A brief introduction to the theory of propagation of waves in random media is presented with approximations often used in the studies of ionospheric scintillation. Numerical models of use in the prediction of scintillation are presented. Influence of various parameters characterizing irregular structure of the ionosphere on scintillation is discussed. In particular effects of the irregularity spectrum, shape of irregularities, geometry of the propagation path etc., are illustrated using scintillation simulations. Magnetospheric Satellite Data: Cluster Maria Federica Marcucci, Istituto Nazionale di Astrofisica-Istituto di Astrofisica e Planetologia Spaziali, Italy The ESA Cluster mission comprises 4 satellites equipped with identical instruments providing high quality measurements of ions and electrons and of magnetic and electric fields. It was launched in 2000 to investigate the three dimensional structure of the Earth's plasma environment, separating unambiguously spatial from temporal variations, and provide a new insight on the Sun Earth connection processes. During the mission, the inter-satellite distance changed from 100 km up to km and the Cluster flotilla visited all the key plasma regions of the near Earth space: the bow shock, the magnetopause (both at high latitudes and near the sub solar point), the cusps, the geomagnetic tail, the inner magnetosphere and the auroral region. Here, some of the relevant results achieved throughout the analysis of the Cluster data are illustrated. The eswua (electronic Space Weather upper atmosphere) system supporting TRANSMIT prototype Vincenzo Romano, Eleftherios Plakidis, Istituto Nazionale di Geofisica e Vulcanologia, Italy In this short presentation, our focus will be on the electronic Space Weather upper atmosphere, (eswua), system, dedicated to the scientific studies of upper atmosphere and more specifically Ionosphere. This information system relies on real-time data coming from specialized instruments installed in strategic locations around the globe, and a sophisticated hardware/software architecture hosted at INGV premises. For the end-users the interfacing with the system is realized via a web-portal, where various services have been deployed and are available to support this knowledge discovery experience in the research field of Upper atmosphere physics. During this presentation we will have an opportunity to explore further the interworking of eswua system and become acquainted with its unique features. Special attention will be also paid on its recent hardware/software expansion to accommodate the requirements of the TRANSMIT Data System. A live demonstration of the system will be shown and some simple use-cases of the TRANSMIT Data System will be also presented.

3 Correction Approaches for Mitigating Ionospheric Higher Order Effects in GNSS Applications Mainul M. Hoque, Norbert Jakowski, German Aerospace Center (DLR), Germany Ionosphere is a significant error source for users of the Global Navigation Satellite Systems (GNSS). Ionosphere induced range errors vary from a few centimeters to tens of meters at zenith. The first order ionospheric term may fully be removed by differencing the signal at two frequencies. In this approach, the higher order ionospheric terms which can be several tens of centimeters at low elevation angles and during times of high total electron content (TEC), are not fully compensated. The higher order ionospheric terms represent large errors in geodetic measurements. Therefore, the studies of the impact of the higher order ionospheric terms on GNSS positioning and their corrections have become relevant and important. In this lecture a rigorous treatment of high order ionospheric terms is presented. Different approximation formulas are discussed to correct errors due to ray path bending errors such as excess path length in addition to the free space path length, TEC difference at two GNSS frequencies, and the second- and third-order ionospheric terms. The GNSS dual-frequency residual range errors can be corrected within millimeter level of accuracy using such correction formulas. Space Weather Impact on Critical Infrastructures Joaquim Fortuny-Guasch, European Commission Joint Research Centre, Italy The activities on space weather at the EC Joint Research Centre started back in 2008, in the framework of the European Programme for Critical Infrastructure Protection. This talk will give an overview of the critical infrastructures potentially disrupted in case of a severe space weather event. A summary of the work carried out on the testing of commercial GPS timing receivers will be given, underlining the need to make them more resilient in case of a GNSS signal outage or under severe ionospheric scintillation. Furthermore, the talk will include a briefing on the results of two monitoring campaigns at the Jicamarca Radio Observatory (Peru) and at the Hanoi Science and Technology University (Vietnam), where the JRC is collecting intermediate frequency (IF) datasets using a software radio platform (USRP from Ettus Research) capable of recording the GNSS RF signal at L-band at 5 MS/sec, which shall be sufficient to record scintillation events both on the GPS and Galileo open signals. The availability of this library of IF datasets is key to assess quantitatively the level of robustness of commercial receivers used in critical applications as if they were operating in the field under strong ionospheric scintillation conditions. Ionospheric Precursors to Scintillation Activity Paul Stephen John Spencer, European Commission Joint Research Centre, Italy Ionospheric scintillation is the rapid fluctuation of both phase and amplitude of trans-ionospheric radio waves due to small scale electron density irregularities in the ionosphere. Irregularities are created by a range of physical mechanisms and are mainly located in the equatorial and polar F region. Prediction of the occurrence of scintillation at L band frequencies is needed to mitigate the disruption of space-based communication and navigation systems. In this paper a combination of scintillation measurements obtained from ground-based and space-based GPS receivers (COSMIC) are related to observations of the ionosphere as observed with ionosondes and GPS. It is shown that knowledge of the ionosphere can be used to provide an advanced warning of the probability of severe scintillation.

4 3 rd July Radio Direction Finding and Navigation Tomislav Kos, University of Zagreb, Faculty of Electrical Engineering and Computing, Croatia The lecture will address methods and techniques that use radio signals for positioning. GNSS receivers work impeccably only outdoors and with a clear view to the sky. Accurate indoor positioning and navigation, where GNSS signals are very weak, is rather difficult to provide. As we spend most of the time indoors, at the office, on campus, in shopping centres, restaurants, etc., indoor positioning is a great challenge for researchers. The demand for location-based services is growing exponentially, mainly because of rapidly expanding Smartphone market. Smartphones are equipped with various sensors: accelerometers, gyroscopes, compasses, Wi-Fi and Bluetooth, making indoor positioning possible. Smartphone mapping system uses augmentation of GNSS with cellular base station signals and Wi-Fi hotspots. Smartphones are capable of tracking GPS and GLONASS signals and integrate positioning from GNSS and other sensors to generate accurate and reliable position updates, enabling people to find their way and enjoy a variety of location-based services and applications seamlessly, indoors and outdoors. The lecture will explore how different kinds of radio signals can be used for positioning, and will give an overview how alternative positioning techniques work. The Role of GNSS software receivers in Ionospheric Monitoring activities Fabio Dovis, Department of Electronics and Telecommunications, Politecnico di Torino, Italy The advent of the Galileo system in Europe of the Compass 2 in China and the modernization plans for Global Positioning System (GPS) and GLONASS are giving a strong impulse to development of global navigation satellite systems (GNSS) services and applications. The next generation of receivers will have to deal with signals in different bandwidths with different modulation schemes. In such a context the reconfigurability offered by software defined radio (SDR) technologies, can play an important role. Furthermore, new advanced signal processing algorithms for estimating and mitigating impairments such as ionospheric scintillations, interference and multipath are proposed. The integration of such algorithms in the receivers becomes of paramount importance to grant the accuracy and reliability of the GNSS positioning for the applications. Fully software implementations are then an efficient tool for the design and validation of the algorithms, thanks to the flexibility and reconfigurability of the SDR approach. The presentation will discuss the SDR implementation of the GNSS baseband processor and the design choices to meet the real-time constraints. Finally, the use of the SDR receiver for the design of advanced algorithms to the ionospheric monitoring is presented. Mitigation of scintillation effects on GNSS positioning Alan Dodson, Marcio Aquino, University of Nottingham, United Kingdom Mitigation of scintillation effects on GNSS positioning may be approached by different angles. The most simplistic solution would be to discard satellites whose signals are strongly degraded. A better approach however could start at the receiver tracking stage, where techniques aiming at a more robust tracking performance under scintillation conditions can be of great assistance. Further down the line, if tracking can be ensured, or at least improved, then the next best bet could be having access to, and making appropriate use of, the tracking errors that will dictate the quality of the measurements to be used in firmware (or in post-processing) to compute position. Knowledge of these errors on an individual satellite basis can be of significant help in tailoring the least squares stochastic model in the presence of scintillation, giving it a more realistic representation, vis-`a-vis the otherwise equal errors model. This lecture will discuss these varied approaches to scintillation mitigation. Anticipations on Horizon 2020 the EU Framework Programme on Research and Innovation Keji Alex Adunmo, Agenzia per la Promozione della Ricerca Europea, Italy Horizon 2020 is the financial instrument implementing the Innovation Union, a Europe 2020 flagship initiative aimed at securing Europe's global competitiveness. Running from 2014 to 2020 with an 80 billion budget, the EU s new programme for research and innovation is part of the drive to create new growth and jobs in Europe.

5 Horizon 2020 will fund Excellent Science to provide a boost to top-level research in Europe; it will strengthen Industrial Leadership in innovation investing in key enabling technologies, granting greater access to capital and support for SMEs; it will tackle grand Societal Challenges such as climate change, sustainable transport and mobility, affordable renewable energy, 4 th July Ionospheric effects worst case scenarios Kees de Jong, Yahya Memarzadeh, Hans Visser, Fugro Intersite B. V., Netherlands Fugro provides a number of global, high precision GNSS services, mainly to the offshore oil and gas industry. Apart from the GNSS signals themselves, these services also rely on correction signals, broadcast by geostationary satellites using frequency bands similar to GNSS. A lot of activities take place in areas at or near the geomagnetic equator, such as Brazil, West Africa and Southeast Asia. As a result, the GNSS and correction signals are often disturbed or even completely lost, due to e.g. ionospheric scintillations. Using more satellite systems, such as GPS, Glonass, Galileo and Compass, may help, but it would also be beneficial to be able to predict when the ionosphere will start behaving badly and which signals will be affected. In this contribution we will give an overview of the Fugro GNSS services, reference network monitoring and the activities related to ionospheric monitoring and prediction. IONORT: a Windows software tool to calculate the HF ray tracing in the ionosphere Alessandro Settimi, Istituto Nazionale di Geofisica e Vulcanologia, Italy This lecture describes an applicative software tool, named IONORT (IONOspheric Ray Tracing), for calculating a three-dimensional ray tracing of high frequency waves in the ionospheric medium. This tool runs under Windows operating systems and its friendly graphical user interface facilitates both the numerical data input/output and the two/three-dimensional visualization of the ray path. In order to calculate the coordinates of the ray and the three components of the wave vector along the path as dependent variables, the core of the program solves a system of six first order differential equations, the group path being the independent variable of integration. IONORT uses a three-dimensional electron density specification of the ionosphere, as well as by geomagnetic field and neutral particles-electrons collision frequency models having validity in the area of interest. The Near-Earth Space Data Infrastructure for e-science (ESPAS)- EU FP7 project Michael Pezzopane, Istituto Nazionale di Geofisica e Vulcanologia, Italy The region commonly referred to as near-earth space extends from the middle atmosphere up to the outer radiation belts. This region is of significant interest for two reasons: (i) its potentially undesired effects on human life and on technological systems and (ii) scientific exploration and advances. The latter has been a field of intense investigation for more than a century, consequently a wealth of diverse types of observations have been acquired, many of which still need to be homogenized and organized in order to become widely accessible. The former received wider attention only over the last 1-2 decades when researchers and engineers realized the adverse impact large perturbations of the near-earth space environment can have on critical infrastructures, both ground-based and space borne technological systems. This is now recognized as a discipline of its own termed Space Weather in analogy to terrestrial weather. Hence, awareness of space weather conditions is becoming increasingly important for critical systems in modern society. A large variety of different instruments observe near-earth space, providing heterogeneous sets of data with very different distribution policies. ESPAS is an EU FP7 project aiming at integrating diverse datasets by developing a common e-infrastructure for access to observations, models and predictions of the near-earth space environment from the at-

6 mosphere up to the outer radiation belts. ESPAS is implemented as web services, enabling the user to search for all available space weather data fulfilling selected criteria such as spatial and temporal location. Over 20 partner institutes from 11 EU countries and Norway and USA will provide access to more than 40 data repositories containing heterogeneous data from ground and space, both in situ and remotely sensed. This lecture presents an overview and the state of art of the ESPAS project whose outcomes will be definitely of interest to the GNSS community. GNSS data pre-processing: a zero-difference approach Roman Galas, Technische Universität Berlin, Germany The main objectives of the GNSS data pre-processing are: raw data decoding and conversion, detection of outliers in code- and in carrier phases, repair of the receiver clock resets, and detection and correction for the carrier phase cycle slips. Data pre-processing is the first step in each GNSS processing chain, and the cycle slip fixing is the most challenged procedure especially in real-time applications. Algorithms for GPS single station pre-processing techniques, based on the zero difference dual frequency observations, are described in details and evaluation of their performance is given. Some specific issues related to atmosphere delays modelling are discussed as well. The presentation is illustrated with some numerical examples processed with the software application zeroedit. It is a member of the TUB-NavSolutions software suite, consisting of astronomical and GNSS libraries and of various navigation applications, written in C and basically running under Linux-, Unix- and OS X operating systems. The Calibration of Total Electron Content from GNSS Observations Luigi Ciraolo, International Centre for Theoretical Physics, Italy Global Satellite Navigation Systems (GNSS) provide with excellent satellite-to-station (Slant) data of Total Electron Content (TEC), but affected by biases. Estimating these biases is carried out making assumptions on the space/time behaviour of Vertical TEC (vtec), enabling to write observation equations involving the coefficients of the expansion of vtec and the observed slant TECs (STEC). This procedure is named Calibration : expected accuracy and relative problems will be described.

7 5 th July Ground Based Scintillation Climatology Luca Spogli, Istituto Nazionale di Geofisica e Vulcanologia, Italy Reconstructing and modelling the spatial and temporal distribution of the ionospheric irregularities and understanding their impact on trans-ionospheric signals, mostly the so-called scintillations, are one the main issues addressed by the modern Space Weather Science. A climatological approach is one of the key ways to face the complexity of the laws of Nature ruling the coupling of the ionosphere with the other Earth s spheres and leading to the ionospheric variability and dynamics. In fact it is currently widely considered one of the most effective approach to assess the general recurrent features of the ionospheric irregularities dynamics and temporal evolution, trying to catch eventual correspondences with scintillation occurrence. During the last decade, networks of special GNSS receivers have been deployed over different latitudes in both hemispheres to investigate the ionospheric scintillations, trying to understand the physical processes producing them. Recently, a statistical technique called Ground Based Scintillation Climatology (GBSC) has been developed, to prove insights about the cause-effect mechanisms producing phase and amplitude scintillations, suggesting the different roles of the main ionospheric areas in hosting those irregularities causing scintillations. In this lecture the main results of the GBSC are presented, together with an introduction and a comparison with the main climatological model of scintillation, as the WAM and WBMOD. Receiver Integrity Monitoring Station Samuele Fantinato, Thales Alenia Space Italia, Italy The Receiver Integrity Monitoring Station (RIMS) is a key subsystem of the ground mission segment in the EGNOS system as well as its correspondent GRCN element within the Galileo Ground Mission Segment. These elements have the important function of receiving, acquiring and tracking all the satellite constellation signals in view of the station, producing very accurate code, carrier and Doppler measurements and sending these measurements to the Central Processing Facility which uses them to compute and produce the Orbit Determination and Time Synchronization products as well as generating Integrity information. The RIMS are placed in stations all over Europe and currently extending their geographical locations also to Africa, Middle East and Polar regions. Those regions (equatorial and polar) suffer from higher ionospheric scintillation effects and therefore the RIMS receivers are required to include more robust tracking functions as well as on-line functions for ionospheric effects monitoring. Future evolutions of the EGNOS system is foreseeing RIMS receivers that will have multi-constellation and multi-frequency capability and flexibility to be reconfigured to track any kind of signal in view. Those RIMS will also possibly include on-line and off-line RF environment monitoring elements. The presentation will focus on the station architecture, its main features, and on the receiver processing with special attention on ionospheric robustness and monitoring. A view on the receiver evolutions and new technologies will also be presented. Spaced Receivers Marcin Grzesiak, Andrzej Wernik, Space Research Center, Polish Academy of Sciences, Poland The amplitude, phase, and angle of arrival of the signals traversing the ionosphere are distorted by drifting small scale plasma density irregularities. Fluctuations of the wave parameters are called scintillations. Scintillations, when measured on the ground, provide information about the structure and motion of ionospheric irregularities. The lecture will present a short panorama and perspectives of multipoint experiments diagnostics. The aim of the spaced receivers experiment is estimation of the diffraction pattern drift velocities and anisotropy of scintillation producing electron density irregularities. Starting from simple models of a physical system time evolution a concise justification of techniques will be given. We present the possibility of estimation of other parameters and give examples of analysis of multipoint measurements other than experiments based on GNSS. We also sketch possible directions of methods development.

8 The Inversion of Ionograms and Electron Density Profile Models Carlo Scotto, Istituto Nazionale di Geofisica e Vulcanologia, Italy The existing models of electron density profile in the ionosphere were mainly obtained by using data coming from the inversion of ionograms. The problems inherent in this operation are shown. It is necessary to make assumptions on the distribution of ionization and the index of refraction of HF radio waves. The lesson is completed with numerical examples. Cloud Environment Supporting GNSS Based Services Lorenzo Mossucca, Klodiana Goga, Istituto Superiore Mario Boella, Italy Cloud Computing has become a scalable services consumption and delivery platform in the field of Services Computing. Cloud is a platform or infrastructure that enables execution of code (services, applications), in a managed and elastic way. The aim of this talk is to put the emphasis of e-science applications and technological progress on cloud solutions and infrastructures. In particular concerning research activities on resource control, vertical and horizontal scalability, adaptability using effective scheduling for the virtualization. Due to the high computing performances required, nowadays GNSS application is used only for scientific purposes and not as a real time tool. Cloud solutions have a twofold aim, on one side to improve the computing resources availability for GNSS real time application, while on the other to optimize the algorithm for dynamic and real time application, towards a service. Pathways to Science Outreach Federica La Longa, Massimo Crescimbene, Istituto Nazionale di Geofisica e Vulcanologia, Italy Science Outreach offers crucial added value for a research project. The communication of science to the public is part of a researcher's responsibility as defined by the European Charter for Researchers: Researchers should ensure that their research activities are made known to society at large in such a way that they can be understood by non-specialists, thereby improving the public's understanding of science. Direct engagement with the public will help researchers to better understand public interest in priorities for science and technology and also the public's concerns". Outreach activities entail communications initiatives directed to the general public, rather than the research community. The goal of this activity is to create awareness among the general public about the research work performed and its implications for citizens. As well as raising the profile of a research project with the general public, outreach activities should also introduce students from schools and universities to science, research and innovation. Participants will explore some pathways to science outreach through communication plays and role-playing activities.