Matches in SemOpenAlex for { <https://semopenalex.org/work/W2807685000> ?p ?o ?g. }
Showing items 1 to 59 of
59
with 100 items per page.
- W2807685000 abstract "Geodetic Very Long Baseline Interferometry (VLBI) is an essential technique for space geodesy. It is uniquely capable of simultaneously observing all Earth Orientation Parameters (EOP) and directly giving access to the Earth’s rotation angle (related to Universal Time, UT1). The EOP provide the link between the terrestrial and celestial reference frame. The latter is defined by positions of extra-galactic radio sources observed with geodetic VLBI whereas the terrestrial frame is realised through station positions and velocities. Ongoing phenomena such as the sea-level rise caused by global warming have magnitudes in the millimetre per year range. An accurate global reference frame is therefore crucial for reliably measuring these changes. The Global Geodetic Observing System (GGOS) and its VLBI component, the VLBI Global Observing System (VGOS), are designed to meet these challenges. The transition to the VGOS era brings challenges for all aspects of geodetic VLBI: telescope design, receiver development, recording, data transfer, correlation, observation planning, and analysis. The transition to VGOS involves gradually phasing out the legacy dual- frequency S/X telescopes, while delivering all IVS geodetic products and ensuring the continuity of the time series of geodetic parameters. The VGOS targets include continuous observations and delivery of initial geodetic products in less than 24 hours. This will require a fully automated VLBI analysis chain to make results available in near-real time. This thesis aims at contributing to the improvement of current geodetic VLBI products and supporting the transition from the legacy S/X systems to observations in the VGOS era. Broadband VGOS observations necessitate upgrades for the receiver chain and the data recording devices. The Onsala Space Observatory (OSO) operated its analogue and a new digital back-end in parallel for almost two years. We present the results from a comparison, in which the new system was found to have no biases w.r.t. the old setup. We also investigate ways to improve the current IVS Intensive sessions. This involves using approaches that have relevance for the upcoming VGOS observations. We present fully automated analysis of INT1 sessions between 2001 and 2015 to investigate different analysis strategies and the impact of mapping functions, the use of auxiliary data, and lack of recent a priori EOP on the UT1-UTC accuracy. Up-to-date a priori polar motion was recognized as a key factor for the accuracy of UT1 estimates. Results from implementation and testing of fully automated robust L1-norm based ambiguity estimation are presented. We find that the L1-norm outperforms least-squares for ambiguity estimation. Lastly, optimal locations for a third station in tag-along mode for INT sessions are determined. We conclude that UT1-UTC WRMS can be reduced to 61 % (INT1) and 67 % (INT2) of the WRMS without the tag-along station. The UT1-UTC was improved significantly even without optimised schedules." @default.
- W2807685000 created "2018-06-13" @default.
- W2807685000 creator A5015606713 @default.
- W2807685000 date "2018-01-01" @default.
- W2807685000 modified "2023-09-27" @default.
- W2807685000 title "Observation strategies for current and future geodetic very long baseline interferometry" @default.
- W2807685000 hasPublicationYear "2018" @default.
- W2807685000 type Work @default.
- W2807685000 sameAs 2807685000 @default.
- W2807685000 citedByCount "0" @default.
- W2807685000 crossrefType "journal-article" @default.
- W2807685000 hasAuthorship W2807685000A5015606713 @default.
- W2807685000 hasConcept C126042441 @default.
- W2807685000 hasConcept C127313418 @default.
- W2807685000 hasConcept C13280743 @default.
- W2807685000 hasConcept C172849965 @default.
- W2807685000 hasConcept C41008148 @default.
- W2807685000 hasConcept C58754882 @default.
- W2807685000 hasConcept C60229501 @default.
- W2807685000 hasConcept C62649853 @default.
- W2807685000 hasConcept C76155785 @default.
- W2807685000 hasConcept C79896159 @default.
- W2807685000 hasConceptScore W2807685000C126042441 @default.
- W2807685000 hasConceptScore W2807685000C127313418 @default.
- W2807685000 hasConceptScore W2807685000C13280743 @default.
- W2807685000 hasConceptScore W2807685000C172849965 @default.
- W2807685000 hasConceptScore W2807685000C41008148 @default.
- W2807685000 hasConceptScore W2807685000C58754882 @default.
- W2807685000 hasConceptScore W2807685000C60229501 @default.
- W2807685000 hasConceptScore W2807685000C62649853 @default.
- W2807685000 hasConceptScore W2807685000C76155785 @default.
- W2807685000 hasConceptScore W2807685000C79896159 @default.
- W2807685000 hasLocation W28076850001 @default.
- W2807685000 hasOpenAccess W2807685000 @default.
- W2807685000 hasPrimaryLocation W28076850001 @default.
- W2807685000 hasRelatedWork W1622047813 @default.
- W2807685000 hasRelatedWork W201147274 @default.
- W2807685000 hasRelatedWork W2157947912 @default.
- W2807685000 hasRelatedWork W2182422153 @default.
- W2807685000 hasRelatedWork W2229553267 @default.
- W2807685000 hasRelatedWork W2238515284 @default.
- W2807685000 hasRelatedWork W2558076278 @default.
- W2807685000 hasRelatedWork W2578401543 @default.
- W2807685000 hasRelatedWork W2580569213 @default.
- W2807685000 hasRelatedWork W2581241535 @default.
- W2807685000 hasRelatedWork W2589367426 @default.
- W2807685000 hasRelatedWork W2742358112 @default.
- W2807685000 hasRelatedWork W2766640883 @default.
- W2807685000 hasRelatedWork W2787829145 @default.
- W2807685000 hasRelatedWork W2804278204 @default.
- W2807685000 hasRelatedWork W2883759669 @default.
- W2807685000 hasRelatedWork W3007943603 @default.
- W2807685000 hasRelatedWork W3035727691 @default.
- W2807685000 hasRelatedWork W3207420601 @default.
- W2807685000 hasRelatedWork W947967050 @default.
- W2807685000 isParatext "false" @default.
- W2807685000 isRetracted "false" @default.
- W2807685000 magId "2807685000" @default.
- W2807685000 workType "article" @default.