National Repository of Grey Literature 6 records found  Search took 0.00 seconds. 
Contribution to Monitoring of Galileo Open Service
Douša, Jan ; Kala, Michael ; Václavovic, Pavel ; Bezděka, Petr
Since 2018, the analysis center of the Geodetic Observatory Pecný (GOP) of the Research Institute of Geodesy, Topography and Cartography has contributed to navigation performance monitoring of the Galileo Open Service (OS) Signal in Space (SIS). The activity is performed within the Member States support of the Galileo Reference Centre (GRC), the GRC-MS project. The contribution consists of the four main tasks: 1) monitoring of the quality of multi-GNSS data from 65 GRC-MS reference stations, 2) generating merged and quality controlled navigation files, 3) generating reference GPS and Galileo satellites orbit and clock products with a maximum latency of 6 and 42 hours, and 4) estimating selected key-parameter indicators for the Galileo OS navigation performance consisting of the service volume availability of dual-frequency OS SIS and PDOP < 6, and the site-measured horizontal and vertical positioning service accuracy. The main advantage of the GOP monitoring processes including all the mandatory inputs consists in used tools (the G-Nut software), reference products (GOP rapid precise satellite orbits and clocks), and consolidated navigation messages, in particular their independence from the service provider or any GRC or GRC-MS solution.
Acceleration of PPP Integer Ambiguity Resolution When Emploing Ionospheric Delays
Nosek, Jakub ; Václavovic, Pavel ; Zhao, Lewen ; Douša, Jan
Precise Point Positioning (PPP) is a powerful method for GNSS data processing, when observations from only one receiver are utilized. Since any systematic error is not eliminated by between-stations differencing, introduced precise products and models are crucial for precise positioning. While precise satellite orbits and clocks corrections are essential for traditional float PPP, satellite phase biases are required for integer ambiguity resolution (PPP-AR). When considering also local ionospheric and tropospheric parameters, the integer ambiguity resolution is achievable very fast, which helps to reduce the initial convergence significantly. When exploiting such precise atmospheric corrections, the solution can be considered an alternative for the popular Real Time Kinematic (RTK) method. Therefore, the solution is usually abbreviated by PPP-RTK. We processed daily GNSS data from EUREF Permanent Network (EPN) using PPP, PPP-AR, and PPP-RTK. The tropospheric delay was not introduced as a product but estimated together with other parameters. The assessment of the convergence time has shown a significant benefit of the resolved integer ambiguities. The average time to reach 10 cm horizontal accuracy was 22, 11, and 7 min when processing in PPP, PPP-AR, and PPP-RTK mode, respectively. The first fixed epoch was obtained after 10 and 2 minutes in the case of PPP-AR and PPP-RTK, respectively. The accuracy assessment of Slant Total Electron Content (STEC) estimated at collocated stations showed their good consistency expressed by the average standard deviation of 0.08 TEC Units.
Geodetic Observatory Pecny GNSS Analysis Supporting Solid Earth Tide Modelling
Nosek, Jakub ; Douša, Jan ; Václavovic, Pavel ; Běloch, Lukáš
The TILDE project deals with local solid Earth tide (LSET) modeling based on direct LSET observations using long-term GNSS time series. Geodetic Observatory Pecný of the RIGTC contributes to the TILDE project by processing GNSS data. We collected GNSS data from 98 stations, which were divided into three subnetworks. Quality control of all observational data was performed using advanced tools from the G-Nut library. High-accuracy GNSS processing using the GNSS-PPP method was performed using REPRO_2020 precise products by the CODE. The results were coordinate displacement component data. Based on these data, LSET models from individual critical areas will be created. These LSET models can be used to assess the risks of earthquakes and volcanic activity caused due to LSET.
Bob Krčil
Douša, Jan ; MOUCHA, Josef (advisor) ; Buddeus, Hana (referee)
The life and work of Bob Krčil have so far been known from fragments and unsubstantiated legends. The aim of this essayistic piece is to lay out the deeper motives of his personal trajectory, photographic oeuvre, and activities for the Czech exile community. Krčil’s photographic body of work is inseparably connected with his eventful life. The writing of the thesis was preceded by tracking down and putting together Krčil’s fragmented estate, sorting out his correspondence and writings, and interviewing people who knew him personally. By drawing on these materials, the thesis aims to provide insight into the life and motivations of this important figure of Czech exile culture.
New documents
Douša, Jan ; KOLÁŘ, Viktor (advisor) ; BÁRTA, Jaroslav (referee)
The goal of this thesis is to demonstrate on specific examples the most current documentary approaches in photography since 2000. The selection focuses on authors whose initial stimulus for their work comes from the fascination with the complexity and visuality of the outside world and from the urge to reflect on this fascination through the medium of photography. Purely conceptual and other approaches that use documentary photography merely as a platform for criticism and analysis of the medium of photography (with its relation to aesthetization or objectivity) are not included in this thesis. The selection of authors, due to the limited nature of the thesis, is not exhaustive. The thesis does not aim to serve as an overview, rather it presents a personal selection of representative authors balancing a wide scope of documentary approaches in their work. The latter include reinvented formal approaches derived from the tradition of the New Documents exhibition which I consider to be an important milestone in the post-war history of documentary photography, but also entirely fresh approaches, or new symbioses thereof. Historical context and critical discourse originating in the 1970s, which questions the documentary functions of photography in combination with aesthetization, create a background for the analysis of contemporary authors.
Kvalita vnitrofiremní komunikace
Douša, Jan ; Janoušková, Alena (advisor) ; Jirásek, František (referee)
Diplomová práce se zabývá komunikací a kvalitou a hledá mezi nimi průnik. Cílem je odpovědět na otázku, co je to kvalita komunikace, jak ji měřit a jak ji dosáhnout. Východisky jsou současné trendy obou oborů a dosažený teoretický výsledek je v druhé části práce aplikován na konkrétní situaci v podniku. Tématem, který práce řeší jsou přeplněné emailové schránky zaměstnanců firmy. Zde je úkolem podrobněji analyzovat současnou situaci pomocí výzkumu a na jeho základě s ohledem na teoretickou úvahu definovat požadavky na kvalitu komunikace ? nyní již v konkrétní podobě. Výstupem je pak návrh řešení jak situaci řešit a to pomocí implementace jiného komunikačního nástroje, který bude nejlépe vyhovovat vzneseným požadavkům.

See also: similar author names
1 Douša, J.
1 Douša, Jan Bc.
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