Regional comparison of absolute gravimeters, EURAMET.M.G-K2 key comparison

In the framework of the regional EURAMET.M.G-K2 comparison of absolute gravimeters, 17 gravimeters were compared in November 2015. Four gravimeters were from different NMIs and DIs, they were used to link the regional comparison to the CCM.G.K2 by means of linking converter. Combined least-squares adjustments with weighted constraint was used to determine KCRV. Several pilot solutions are presented and compared with the official solution to demonstrate influences of different approaches (e.g. definition of weights and the constraint) on results of the adjustment. In case of the official solution, all the gravimeters are in equivalence with declared uncertainties. == Main text To reach the main text of this paper, click on Final Report [http://www.bipm.org/utils/common/pdf/final_reports/M/G-K2/EURAMET.M.G-K2.pdf] . Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/ [http://kcdb.bipm.org/] . The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA)

Quality Indicator for Ionospheric Biases Interpolation in the Network RTK

This paper presents the methodology and performance of an ionospheric quality indicator in the Network RTK. A new index called Zenith Ionospheric Residual Interpolation Uncertainty, which is an extension of the existing indicator is proposed and evaluated using the reference station test network. The dataset used for this study was collected during ionospheric storm period in order to test the indicator during disturbed ionospheric conditions. The test results show that the proposed indicator provides a realistic prediction of ionospheric interpolation accuracy and can be used to predict the Network RTK performance at rover location

Monitoring of the long-standing changes of the absolute gravity in Observatory of Józefosław and at main tectonics units of Poland territory

Gravimetric investigations of the long-standing, not tidal variations of the absolute gravity using ballistic FG - 5 No. 230 gravity meter, bought by Warsaw University of Technology at 2005, were performed on four stations outside the Teisseyre - Tornquist Zone (T - T Zone) as well as at Józefoslaw Astro - Geodetic Observatory of the Warsaw University of Technology, located near Warsaw, near the northern edge of T - T zone on Precambrian Platform. Raw results of observations were corrected by Earth's tide influences, loading effects of the Earth's crust and ocean, by polar motion influence to the gravity as well as from the reason of gravitational and deformation influences of the atmosphere. Monitoring of the gravity on Józefosław station, during three years once a month, pointed out quasi-periodic non-tidal variations. Absolute gravity determinations in previous campaigns (1992 - 2001) on Polish territory were performed using various ballistic gravity meters, many types and quality, as well as there were spread in time. In epochs since 2006 to 2008 with our instrument FG - 5 No. 230 there were obtained the gravity values minor on all investigated stations. It was about 17 žGal on Satellite Lamkówko station, near Olsztyn, and 12 žGal in Borowiec Astro Geodynamical Observatory of the Space Research Centre, Polish Academy of Sciences with comparison to the results from 8 - 10 y earlier obtained using Polish absolute gravity meter ZZG, Italian IMGC and two FG-5 instruments from Austria and USA. The variation since 1996 to 2006 on Giby (station of the gravity national fundamental net) was appeared as only 7.5 žGal. On very stable station Ojców (Seismic Observatory of the Polish Academy of Sciences) located on Świętokrzyskie Mts. craton, the decrease of gravity equal to 9 žGal has been noticed after 9 years. Recovered variations of gravity on Poland territory might have the sources in gravity global or regional variations in the hydrological influences in the vicinity of stations as well as in incorrect earlier determinations of the gravimetric corrections, mainly in vertical gradient of gravity above absolute stations

The feasibility of applying automatic target recognition in trigonometric levelling

The obtained results of the field experiments fully confirmed the feasibility of applying ATR systems in trigonometric levelling. In the tested span experiment at Józefosław, the value difference of height differences obtained with precise geometric levelling and the mean value of all measurements differed by a mere 2.7 mm, and for midnight measurements - it did not exceed 1 mm. The measurements made in the Pieniny Range were also successful in the case of observation compatibility and limiting the impact of atmospheric refraction on measurement results. Unfortunately, the comparison of the obtained height differences with those of 5 years ago showed considerable discrepancies stemming from benchmark subsiding rather than technological accuracy of trigonometric levelling. To verify this thesis it is planned to repeat trigonometric measurements on the testing ground in the Pieniny and to carry out control measurements by means of precise geometric levelling. Summing up, one can note that the use of tacheometers along with ATR enables to automate measurements and related quasi-continuous observations. These traits enable moreover: - to increase the number of observations, and what follows, increase accuracy and reliability of the zenithal length determined, - to average measurements made over a long period, which enables to undermine the influence of atmospheric refraction on the value of height difference measured, - to make observations in different atmospheric conditions, including nighttime when the atmosphere is stable, - to eliminate personal errors of the observer, - to analyze conducted observations in real time

Multipath effect analysis on selected points in control network "Wióry"

Geodetic networks are a basic constructions periodically measured on engineering constructions. They usually joint two objects: control objects and reference objects. Physical points and geodetic observations realize it. Moreover, the reference points and control points have to be checked for their stability and measuring technique (visibility between reference and control points for terrestrial observations, multipath effect for satellite obseryations). Multipath effect analysis on selected points in control network "Wióry" is presented in the paper