Projects / Programmes
Determination and evaluation of irregular solar activities' impact to satellite positioning
| Code |
Science |
Field |
Subfield |
| 2.08.00 |
Engineering sciences and technologies |
Telecommunications |
|
| Code |
Science |
Field |
| T180 |
Technological sciences |
Telecommunication engineering |
| Code |
Science |
Field |
| 2.02 |
Engineering and Technology |
Electrical engineering, Electronic engineering, Information engineering |
Location based services, navigation satellites, GPS, GLONASS, EGNOS, GALILEO, telecommunications, radio communications, single-frequency receivers, geodetic receivers, SIGNAL reference network, sunspots, solar flares, magnetosphere, ionosphere, TEC, data processing, analysis, position degradation, position scattering, environmental alarm
Researchers (18)
Organisations (3)
Abstract
In the hypothesis we declared that different forms of solar activities have impact on the availability, feasibility and quality of location based services (LBS) that are based on the determination of location by global navigation satellite systems (GNSS). The second, from the standpoint of applicability more important statement of the hypothesis, argues that the type of impact by solar activities on the quality of service can be classified for every type of activity.
GNSS systems, like GPS, GLONASS, Galileo and EGNOS, enable positioning on the Earth’s surface with the accuracy from several meters down to 2 cm in real time. This is true for the periods of calm space weather conditions, which depends mostly on the solar phenomena. The increased or extraordinary solar activities (like sunspots, proton bursts, X ray flares, solar wind) are reflected mostly on the value of TEC (Total Electron Content) in the Earth's ionosphere. The value of TEC critically influences the satellite signals and this disturbance deteriorates the quality of satellite positioning on the Earth, which is used in everyday services. The goal of the project is to pin-point those massively used LBSs for positioning which are vulnerable because of increased solar activities, and, to explain how strong this impact is.
The team of researchers is therefore interdisciplinary: the Faculty of Electrical Engineering has experts from the fields of telecommunication, satellite toll collection, and aeronomy; the Geodetic Institute of Slovenia is the national operator of the Slovenian permanent GNSS stations network (SIGNAL) for real time positioning, and co-creator of the new national coordinate system; the Faculty for Civil Engineering and Geodesy has experts from the fields of GNSS, precise geodetic measurements and computations.
Following the hypothesis, we declare that:
the solar activity influences the dissipation and the accuracy of satellite based position measurement of a chosen tie-point,
there are different categories of LBSs that are sensitive to solar activities,
duration, variety and magnitude of solar activity can be classified according to their impact on a range of LBS types, without knowing the ionospheric conditions,
for different LBS services several types of environmental alarms can be established based on the study of past solar events and predictions freely available at space weather prognostic centers and web sites,
these alarms are applicable to support the services, which already exist or will exist in the future in Slovenia (Slovenian permanent GNSS stations network SIGNAL, satellite based toll collection, military applications, geomagnetic reference network).
The project has the following phases:
The analysis of relevant solar activities,
The analysis of relevant parameters of satellite positioning with GNSS from the standpoint of solar disturbances,
The elaboration of strategy for joint computational adjustment of position measurements and detected solar activities,
The definition and acquisition of input data,
The execution of tests, measurements and correlations, which will lead to a positive demonstration of the hypothesis,
The classification of reliability and availability of satellite positioning regarding solar activity,
The identification of potential application fields and measures.
In common LBS we use mainly low-cost GNSS receivers, which have to function in all circumstances without deterioration of positioning. If solar activity is increased, the services can suffer temporary outages, which may cause significant financial losses and expenses. An increasing number of these simple receivers is used also in the fields, where the degradation of positioning means a direct threat to national or personal security and to economic viability. Therefore, it is important to classify such services with respect to the allowed marginal values of accuracy and provide mechanisms of alarming in advance and additional explanation
Significance for science
The declared hypothesis, and thus the results of the project reflect the specificities of dealing with GNSS signals at intervals close to the peaks of solar cycles, where the dynamics of the ionosphere is increasingly changed. The results of initial deep analyses provide a classification of the origin and propagation of solar phenomena activities and their effects on satellites’ orbits, magnetosphere, ionosphere and, finally, GNSS receivers. The presented cause-and-effect model with transfer functions also serves as the basis for all further research, showing the links between various solar activities and corresponding effects on near-Earth observations. Another important result is shown in a form of chronologically composed list of observed solar phenomena since 2000, which includes an explanation of selection criteria, the list of available measurements and methods of their acquisition and unified formatting. The featured procedures and datasets can be used at all related areas where the solar dynamics represents a possible cause of interest. The results of the analysis of satellite positioning are important for the understanding of subsequent approaches to processing of the GNSS signals observations as they provide a comprehensive list of methods of absolute and relative positioning, implementation of one or more receivers, use of single or more carrier frequencies, and code or phase observations. The effects of the ionosphere on the propagation of electromagnetic waves are explained depending on the ionosphere’s parameters, and possibilities of eliminating certain effects by introducing functional models that represent the influences as a set of variables. A detailed examination of procedures for acquiring and storing the data, including real-time dissemination, will be beneficial to all further steps that require the GNSS segment assessment. The results of the analysis of affected GNSS services address the identified groups of important services by their methods (C/A, DGPS, RTK VRS). These satisfy the criteria of national importance, number of users, availability of input datasets and technology limitations. Identified services allow the direct correlation with observations of the Slovenian permanent GNSS network SIGNAL, which is particularly important for the national research activities. The results of test computations provide correlations between the solar phenomena and timely corresponded GNSS observations. The execution functions were refined throughout the processing phase resulting in the design of advanced algorithms that determine the influential model of the changing ionosphere parameters and increased radio noise to the GNSS performance. The discovery of possible GNSS signal outage due to decreased signal-to-noise ratio is very important because it can occur without previous indicators observed in the ionosphere. In case of reception of strong noises over the GNSS carrier bands there is no possibility to raise an alarm in advance since the moments of GNSS receiver saturation coincide with the monitoring stations observation time. It is thus possible to provide trusted alarming mechanisms for ionosphere changes only for slower phenomena like coronal mass ejections with typical propagation delay of about 2 days. For photonic events including radio noise only a probability prediction can be made with respect to the observed activities in the solar atmosphere. The excellence of performed project results will continue to accelerate interdisciplinary scientific cooperation and standardization activities in the area of GNSS services, including the ongoing collaboration in COST Action TU1302 (SaPPART). The project partners will disseminate the results at full scale of educational activities. This interdisciplinary training of future professionals will strongly contribute to high-level knowledge of experts in Slovenian and foreign institutions and industry.
Significance for the country
Rapid development and accessibility of communication technologies has enabled the location-based services (LBS) using satellite positioning to become an important part of modern information society. Using the location, kinematics and timing information professional civil services assure continuous operation of intelligent transport systems, cadastral activities, agricultural automation, environment surveying and financially-oriented instruments. The criteria of accuracy, availability, continuity and integrity are essential when using these services. Their abnormal behavior may pose a direct threat to national or personal safety and economic viability, so it is necessary to perform planning and introduction of services with respect to the influence of irregular solar activities. The presentation of performed project to the Slovenian public contributed to an increase of risk awareness that users are facing using satellite navigation. The results in the form of evaluation of possible solar activity effects to the field of GNSS are also useful in other areas, such as energy, telecommunications, computer science, meteorology and various biological systems. The parameter of location is related to around 80 % of all information, residing from media, private and industrial sector, as well as scientific, so issuing the warnings and the correct interpretation of consequences are therefore crucial for the entire society. Project’s immediate effects in Slovenian space are visible foremost in the context of GPS Service authority with the main scope of maintenance and development of permanent GNSS stations SIGNAL within the Geodetic Institute of Slovenia. By provisioning the differential and RTK VRS positioning services e.g. analyzing the GNSS station locations, real-time assessment of observation quality, data flow transmission to users and contractual distributers and RINEX data format distribution and archiving, they reach the target group of 1300 professional users from fields of precision agriculture, construction site supervision, GIS applications data acquisition, managing the land cadaster and monitoring the movements in engineering geodesy and geo-kinematics. Another 25,000 single-frequency code receivers’ users is associated in the areas of traffic navigation , search and rescue and other recreational and leisure activities related to locating with GNSS systems. By maintaining the WEB portal http://www.gu-signal.si/ and additional provisioning of services the information of solar irregular activities is addressed and disseminated among the interested community. The additional benefits for the Slovenian space are represented by the collaboration of the project partners and their interdisciplinary cooperation in other research projects and educational activities. Both faculties and the institute will disseminate the results to the future leaders of LBS research community, increasing the competitive position of Slovenian development and service markets abroad. Finally, through the collaboration with foreign organizations Slovenia has been recognized as a technologically advanced country, which represents an important step towards future inclusion in international projects. The conducted activities in the fields of satellite navigation and aeronomy will Slovenia enable to proceed with additional certification and standardization activities as well as decision-making about the future of location-based systems.
Most important scientific results
Annual report
2010,
2011,
2012,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2010,
2011,
2012,
final report,
complete report on dLib.si
