a1_The aim of this paper is to present the strategy of determination of the reference solution for the ASG-EUPOS (Active Geodetic Network - European Position Determination System) coordinate monitoring system. ASG-EUPOS is a network of permanent GNSS (Global Navigation Satellite System) stations controlled by the Polish Head Office of Geodesy and Cartography (HOGC), which main role is to realize the ETRS89 (European Terrestrial Reference System) in the territory of Poland. The Centre of Applied Geomatics (CAG) of the Military University of Technology (MUT) performs a control processing of the network and it is the leader of the ASG+ (the supporting modules for ASG-EUPOS system real-time services) project within which the coordinate monitoring system was developed. The coordinate monitoring is aimed to assess the actual performance of the GNSS stations and the reliability of the system and its services. The Polish realization of the ETRS89 is also controlled, where the deviation of the actual coordinates from the reference values are monitored. Furthermore, the monitoring enables the analysis of factors that degrade the individual GNSS stations and assess the solution stability which has impact on the quality of the determined geodynamic parameters. The reference solutions (coordinates and their changes over time) were determined according to the recommendations of the IAG sub-commission for the European Reference Frame concerning densification of EUREF. The paper presents the determination of the reference cumulative solution and the results of the processing of a few years long series of GNSS observations. The analysis are performed by the Bernese 5.0 and CATREF software. The results consists of daily and subdaily ASG-EUPOS reference solutions. They are also considered as input data for geodynamic studies to determine the horizontal and vertical velocity fields., a2_Estimation of the individual station velocities is of crucial importance for the ETRF (European Terrestrial Reference Frame) reference frame maintenance to assess the compatibility of the current station position with its catalogue (reference) value and apply coordinate correction if necessary., Karolina Szafranek, Janusz Bogusz and Mariusz Figurski., and Obsahuje bibliografii
The special theory of relativity holds significant interest for scientifi c perspectivists. In this paper, I distinguish between two related meanings of “perspectival,” and argue that reference frames are perspectives, provided that perspectival means “being conditional” rather than “being partial.” Framedependent properties such as length, time duration, and simultaneity, are not partially measured in a reference frame, but their measurements are conditional on the choice of frame. I also discuss whether the constancy of the speed of light depends on perspectival factors such as the idealized defi nition of the speed of light in a perfect vacuum and the Einstein synchronization convention. Furthermore, I argue for the view that the constancy of its speed is a robust property of light according to the conditions of currently acceptable experimental setups pertaining to special relativity, and conclude that this view supports perspectivism. and Speciální teorie relativity je obzvláště zajímavá z hlediska vědeckého perspektivismu. V tomto článku rozliším dva související významy pojmu „perspektiva“ a pokusím se ukázat, že vztažné soustavy lze chápat jako perspektivy za předpokladu, že perspektivou rozumíme spíše „být podmíněný“, a nikoli „být dílčí“. Vlastnosti závislé na vztažné soustavě, jako je délka, časové trvání a simultánnost, nejsou v dané vztažné soustavě měřeny neúplně, ale jejich měření jsou podmíněna výběrem vztažné soustavy. Rovněž se budu zabývat otázkou, zda stálost rychlosti světla závisí na perspektivních faktorech, jako je idealizovaná defi nice rychlosti světla v dokonalém vakuu a Einsteinova synchronizační konvence. Na závěr se pokusím ukázat, že konstantní rychlost je robustní vlastností světla dle podmínek aktuálně přijímaných experimentů týkajících se speciální relativity a že tento pohled podporuje perspektivismus.