An accuracy assessment of Magellan Very Long Baseline Interferometry (VLBI)

Very Long Baseline Interferometry (VLBI) measurements of the Magellan spacecraft's angular position and velocity were made during July through September, 1989, during the spacecraft's heliocentric flight to Venus. The purpose of this data acquisition and reduction was to verify this data type for operational use before Magellan is inserted into Venus orbit, in August, 1990. The accuracy of these measurements are shown to be within 20 nanoradians in angular position, and within 5 picoradians/sec in angular velocity. The media effects and their calibrations are quantified; the wet fluctuating troposphere is the dominant source of measurement error for angular velocity. The charged particle effect is completely calibrated with S- and X-Band dual-frequency calibrations. Increasing the accuracy of the Earth platform model parameters, by using VLBI-derived tracking station locations consistent with the planetary ephemeris frame, and by including high frequency Earth tidal terms in the Earth rotation model, add a few nanoradians improvement to the angular position measurements. Angular velocity measurements were insensitive to these Earth platform modelling improvements

VLBI2010 - The TWIN radio telescope project at Wettzell, Germany

The Twin Telescope Wettzell (TTW) Project is funded to be exec uted during the period of 2008-2011. The design of the TTW was based on the VLBI2010 vision of the corresponding IVS Working Group. In the first two project years the design passed the simulations with respect to its specifications and was approved for production. At the Geodetic Observatory Wettzell a thorough soil analysis was made in order to define the sites for the towers of the new radio telescopes. Meanwhile the construction work has begun and acceptance tests of several telescope parts, e.g. azimuth bearings, took place. The full assembly of the radio telescopes is scheduled for the next two years. In parallel to the construction work at the Wettzell site, the design work for the different feed options progressed

Radio Frequency Interference Observations at IAR La Plata

The Wettzell RFI-Monitoring system was developed to monitor radio frequency interference at existing and potential VLBI sites. It is a transportable system which can be operated in a semiautomated manner. It was used at the Instituto Argentino de Radioastronomía in La Plata to investigate a future site for the Transportable Integrated Geodetic Observatory (TIGO). With the help of an automated pedestal for the RFI-monitoring antenna a 24h/7d survey was conducted during September and October 2012. This data set is one of the most dense RFI-monitoring samples known within the IVS. The results of this survey showed, that most of the present RFI signals occure sporadically and take away less than 5% of the observation time. Hence IAR is a suitable site for TIGO.Fil: Haze, Hayo. Bundesamt Für Kartographie Und Geodäsie-bkg; AlemaniaFil: Gancio Gonzalez, Guillermo Matias. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Perilli, Daniel Oscar. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Larrarte, Juan Jose. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Garcia, Leandro Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Kronschnabl, G.. Bundesamt Für Kartographie Und Geodäsie-bkg; AlemaniaFil: Plötz, C.. Bundesamt Für Kartographie Und Geodäsie-bkg; AlemaniaFil: Guarrera, Leonardo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentina21st Meeting of the European VLBI Group for Geodesy and AstrometryKirkkonummiFinlandiaFinnish Geodetic Institut

Conserved genes and pathways in primary human fibroblast strains undergoing replicative and radiation induced senescence

Additional file 3: Figure S3. Regulation of genes of Arrhythmogenic right ventricular cardiomyopathy pathway during senescence induction in HFF strains Genes of the “Arrhythmogenic right ventricular cardiomyopathy” pathway which are significantly up- (green) and down- (red) regulated (log2 fold change >1) during irradiation induced senescence (120 h after 20 Gy irradiation) in HFF strains. Orange color signifies genes which are commonly up-regulated during both, irradiation induced and replicative senescence

Numerical Investigation Of The Accuracy Of Computerized Ionospheric Tomography Reconstructions For Realistic Receiver Configurations

A comprehensive numerical study of the accuracy of computerized ionospheric tomography (CIT) has been completed. The primary objective of the study was to quantify the error source and degradation in reconstruction accuracy when CIT is applied to real world conditions. Real world deployment of Transit (NSS) receivers will be determined by convenience and availability of sites. Therefore the receivers will not all be in a line, nor will they be directly under Transit passes. Typically there will be a cross dispersion in the locations of the receivers, as well as an angular offset from the north-south direction. Knowledge of how these effects degrade the quality of reconstructed images is important for both the academic and applied communities. Computer simulations of Transit TEC data have been generated for a number of different receiver configurations, data rates, and geophysical locations. The data has been used as input to CIT reconstruction algorithms. The resulting reconstructions ..

Application Of Ionospheric Tomography To Single Site Location Range Estimation

The estimation of transmitter location based on radio frequency reception at a single site has long been a challenge. The standard technique for location estimation has typically used an active local vertical transmitter (ionosonde) to characterize the local ionosphere for propagation path modeling. A technique that is totally passive and yields a more comprehensive estimate of the propagation path is under development at Applied Research Laboratories, The University of Texas at Austin (ARL:UT). This technique uses tomography to describe the two-dimensional state of the ionosphere over wide ionospheric swaths. ARL:UT deployed an array of Transit satellite receivers in nine locations along a 2000 km baseline from Pharr, Texas (TX) to Pierre, South Dakota (SD). Transit signals received at these nine locations were analyzed using tomography algorithms to estimate the electron density distribution in the plane defined by a "best fit" arc through the receiver array and best fit arc along ..