Using software spectrometer to ensure VLBI signal chain reliability

Software spectrometer (SWSpec) developed for spacecraft tracking can be used to assure VLBI signal chain reliability, and phase stability of a VLBI receiver. Testing performed with SWSpec during pre-operations both saves time, and eases the tests as one does not need to gather, couple and setup the hardware.Comment: 4 pages, 4 figures, 12th European VLBI Network Symposium and Users Meeting, 7-10 October 2014, Cagliari, Ital

Metsähovi Radio Observatory - Annual Report 2011

Metsähovi Radio Observatory, a research institute at Aalto University (formerly: Helsinki University of Technology, TKK), operates a 14 m diameter radio telescope at Metsähovi, the village of Kylmala in Kirkkonummi, about 35 km west from the Otaniemi university campus. Metsähovi is active in the following fields: radio astronomical research, multifrequency astronomy and space research, development of instruments and methods for radio astronomy, and (radio) astronomical education. Geodetic VLBI observations are also done in Metsähovi in collaboration with the Finnish Geodetic Institute.In 2011 twenty-two scientists, engineers, research assistants and support personnel worked at the institute. In 2011 the total expenditure of Metsähovi Radio Observatory was 1 338 889 euros including salaries and the rent of the office and laboratory space at the Metsähovi premises. This was funded by Aalto University, Academy of Finland, European Union, and other outside sources

Metsähovi Radio Observatory - Annual Report 2012

Metsähovi Radio Observatory, a research institute at Aalto University (formerly: Helsinki University of Technology, TKK), operates a 14 m diameter radio telescope at Metsähovi, the village of Kylmälä in Kirkkonummi, about 35 km west from the Otaniemi university campus. Metsähovi is active in the following fields: radio astronomical research, multifrequency astronomy and space research, development of instruments and methods for radio astronomy, and (radio) astronomical education. Geodetic VLBI observations are also done in Metsähovi in collaboration with the Finnish Geodetic Institute. In 2012 twenty-four scientists, engineers, research assistants and support personnel worked at the institute. In 2012 the total expenditure of Metsähovi Radio Observatory was 1 678 677 euros including salaries and the rent of the office and laboratory space at the Metsähovi premises. This was funded by Aalto University, Academy of Finland, European Union, and other outside sources

Metsahovi Radio Observatory - IVS Network Station

In 2012, Metsahovi Radio Observatory together with Finnish Geodetic Institute officially became an IVS Network Station. Eight IVS sessions were observed during the year. Two spacecraft tracking and one EVN X-band experiment were also performed. In 2012, the Metsahovi VLBI equipment was upgraded with a Digital Base Band Converter, a Mark 5B+, a FILA10G, and a FlexBuff

Metsähovi Radio Observatory - Annual report 2010

Metsahovi Radio Observatory, a research institute at Aalto University (formerly: Helsinki University of Technology, TKK), operates a 14 – m -diameter radio telescope at Metsahovi, the village of Kylmala in Kirkkonummi, about 35 km west from the Otaniemi university campus. Metsahovi is active in the following fields: radio astronomical research, multifrequency astronomy and space research, development of instruments and methods for radio astronomy, and (radio) astronomical education. Geodetic VLBI observations are also done in Metsahovi in collaboration with the Finnish Geodetic Institute. In 2010 twenty-four scientists, engineers, research assistants and support personnel worked at the institute. In 2010 the total expenditure of Metsahovi Radio Observatory was 1 177 941 euros including salaries and the rent of the office and laboratory space. This was funded by Aalto University, Academy of Finland, European Union, and other outside sources. The past few years have been full of organisational changes in our university. In the introduction of the previous Annual Report I wrote: "These years of reformation have been full of increased administrative load. We are looking forward to the new university taking its form and becoming fully operational, when we will hopefully once again have time to concentrate on scientific research!" Unfortunately I was overly optimistic. Year 2011 was even worse than the ones before that, which is also the reason why our Annual Report 2010 was delayed so much (published in spring 2012). The faculty of Electronics, Communications and Automation that was established in 2008 (and where Metsahovi was merged) ceased to exist in 2011, and now we are part of the Aalto University School of Electrical Engineering (ELEC)

Geodeettisen VLBI:n kehittäminen: UT1:n tarkkuus, tulosten viiveellisyys ja datan laadun monitorointi

In modern geodesy the space-related techniques play an important role. The three most significant of these techniques are the Global Navigation Satellite System (GNSS) that includes the Global Positioning System (GPS), the Satellite Laser Ranging (SLR), and Very Long Baseline Interferometry (VLBI). The next generation geodetic VLBI system, VLBI2010, covers everything from antennas to analysis and is being implemented at VLBI stations globally. One of the key requirements for VLBI2010 is the automation of the data analysis in order to reduce the latency of the results to 24 hours. VLBI is a unique technique for determining the Earth Orientation Parameters (EOP), which are necessary, for example, for navigation satellites. The accuracy of GNSS positioning is related to the accuracy of EOP. Therefore, it is important to measure these parameters with the best possible accuracy and as short latency as possible. In this dissertation the automation of the International VLBI Service for geodesy and astrometry (IVS) intensive sessions is described. In the near future, the Vienna VLBI Software (VieVS) will be implemented with the pre-analysis steps that are currently being developed, the group delay ambiguity resolution and the ionospheric correction. The most commonly used geodetic VLBI analysis software is Calc/Solve that is maintained at the Goddard Space Flight Center (GSFC). So as not to bias the outcome by adopting only one software package, a comparison of Solve and VieVS EOP results was performed. This comparison showed that VieVS analysis appeared to improve the accuracy in the dUT1 result. However, polar motion results were more precise when Solve was used for the analysis. To fulfill the VLBI2010 precision requirements, the effect of source distribution on the dUT1 result accuracy obtained from IVS INT1 experiments was investigated. On the basis of the research conducted in this thesis, the results from the source constellation study show that the accuracy of the dUT1 is affected by the distribution in the sky as seen from the midpoint of a baseline, and will improve when a novel method proposed for scheduling intensive sessions will be implemented. Until now, the sky has been observed from the Kokee Park North direction. Introducing the new concept of observing the sky from a fictitious midpoint of the baseline greatly improves dUT1 accuracy. IVS should take this into consideration, because the accuracy of the results is a significant factor when calculating satellite orbits, for example. VLBI2010 requires shipment of the VLBI data via Internet. Firmware was developed to enable VLBI2010-compatible stations to perform zero baseline correlation tests with the Digital Base Band Converter (DBBC) and FILA10G ethernet board, and thus the stations can check the quality of the data in real-time.Modernissa geodesiassa avaruustekniikoilla on tärkeä rooli. Kolme tärkeintä tekniikkaa ovat globaali satelliittipaikannusjärjestelmä (Global Navigation Satellite System, GNSS, mukaan lukien Global Positioning System, GPS), satelliittilaser (Satellite Laser Ranging, SLR) ja pitkäkantainterferometria (Very Long Baseline Interferometry, VLBI). Seuraavan sukupolven geodeettinen VLBI-järjestelmä, VLBI2010, kattaa kaiken antenneista data-analyysiin. Yksi tärkeimmistä vaatimuksista on analyysin automatisointi, jonka avulla tulokset on mahdollista saada 24 tunnin sisällä korrelloinnista. Tässä väitöskirjassa kansainvälisen geodesian ja astrometrian VLBI-palvelun (International VLBI Service for geodesy and astrometry, IVS) intensiivisessioiden analysointi on automatisoitu sekä Vienna VLBI Software -ohjemistoon (VieVS) lisätään puuttuvia esianalyysivaiheita. Goddard Space Flight Centerin (GSFC) ylläpitämä Calc/Solve-ohjelmisto on yleisimmin käytössä oleva geodeettisen VLBI:n analyysityökalu. Jotta tuloksiin ei tulisi systemaattista virhettä, kun käytetään vain yhtä ohjelmistoa, uudemman VieVS:in tuloksia verrattiin Solven tuloksiin. VieVS antaa tarkempia dUT1-tuloksia, kun taas Solven napavariaatiotulokset olivat tarkempia kuin VieVSin. Jotta VLBI2010-tarkkuusvaatimukset voitaisiin täyttää, tutkittiin dUT1-tuloksia IVS:n INT1-sessioista. Oletuksena oli, että lähteiden sijainti taivaalla kahta teleskooppia yhdistävän viivan keskipisteestä nähtynä vaikuttaa parametriin ja sen virheeseen. Tutkimuksessa todettiin, että ne sessiot, joissa kohteet olivat mahdollisimman kaukana toisistaan, tuottivat tarkimmat tulokset. Väitöskirjatutkimuksessa kirjoitettiin VHDL-firmware niin kutsuttuja 'zero baseline correlation' -testejä varten, joiden avulla voidaan tutkia VLBI-datan laatua

Radio Signatures of Sunspot NOAA 12192

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Total Solar Flux Intensity at 11.2 GHz as an Indicator of Solar Activity and Cyclicity

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