The sound wave displacement-based ultrasonic meter dependence on various atmospheric factors

The dependence of speed of ultrasound in air on various climatic factors operating in the atmosphere has a significant impact on the accuracy of the ultrasonic flow measurement method. The article examines how to analyse, calculate and form mathematical formulas for air speed dependencies on all foreseen atmospheric factors that can affect the accuracy and results of measurements. The results obtained will be used for creating a mathematical model in MATLAB environment. The examination of a great number of sources suggests that a mathematical model of the speed of sound evaluating various influencing factors in a wide range has not been created until now. The article provides a partial analysis on this issue that would be applicable only for a partial application of the model used for an acoustic impulse mete

The sound wave displacement-based ultrasonic meter dependence on various atmospheric factors

The dependence of speed of ultrasound in air on various climatic factors operating in the atmosphere has a significant impact on the accuracy of the ultrasonic flow measurement method. The article examines how to analyse, calculate and form mathematical formulas for air speed dependencies on all foreseen atmospheric factors that can affect the accuracy and results of measurements. The results obtained will be used for creating a mathematical model in MATLAB environment. The examination of a great number of sources suggests that a mathematical model of the speed of sound evaluating various influencing factors in a wide range has not been created until now. The article provides a partial analysis on this issue that would be applicable only for a partial application of the model used for an acoustic impulse mete

Some issues of the national gravimetric network development in Lithuania

The gravity height systems adoption is crucial in development of national geodetic reference. Successful solution of this questions guarantees the reliable determination of geopotential heights, usage of modern geodetic space techniques, maintenance of the navigation, geodetic and cartographic works, solution of geodynamic tasks, support the relations between the similar systems of other countries, participation in the international projects. The gravity and height systems should be related with the geocentric geodetic coordinate system. In Lithuania such a system was adopted in 1994 as a Lithuanian Coordinate System (LKS 94). It is consist with European Terrestrial Reference System 1989 (ETRS 89). With adoption of LKS 94 the normal gravity field GRS 80 was introduced. It was recommend by the International Association of Geodesy (IAG). To introduce the new gravity system instead of Potsdam system the absolute gravity measurements were carried out in 1994. Such measurements were carried out by Jaakko Makinen (Finish Geodetic Institute). Measurements were performed by ballistic gravimeter JILAg-5 in the points VILNIUS, KLAIPEDA and PANEVEZYS. Absolute gravity measurements were repeated in 2002. The 5 µGal precision of the gravity acceleration was derived. Some issues of development of the National gravimetric network are discussed. The main stress is given to the analysis of the precision of the gravity acceleration at the points of the gravimetric network. The calibration of the gravimeters was carried out before and after field survey. The difference of the gravity acceleration of the calibration bases is 202 mGal, and two zero order and two first order points are in it. The standard deviation of the linear scale coefficients of 0.00006 was received. The maximal change of the linear scale coefficients during all time of field campaign was 0.000159 (gravimeter No 183). During the three months of period of investigations the zero drift of the gravimeters was changed from 17 till 197 µGal/day. The National gravimetric network was adjusted using software package GRAVSOFT. Total number of observations is 33777. The three absolute gravity stations were chosen as initial points. Standard deviation of the single observation equal to 5 µGal, and standard deviation of gravity acceleration of the single points equal to 3 µGal were receive

Formalization of the observations of the sea level variations using XML data schemas and scalable vector graphics format

XML (Extended Markup Language) Data Schemas as the format for information exchange in graphical SVG (Scalable Vector Graphics) format is presented in the paper. SVG file format is a language for two-dimensional graphics and is based on XML. It is suggested to apply it as the advanced version of previous data exchange format TGINEX (Tide Gauge Independent Exchange Format), which contains the plain ASCII data. SVG graphics are formatted from the observations of sea level observations by the tide gauges. As an example, the formalization of data is shown on the base of the sea level observing station KLPD, which is a part of the European Sea Level Service network. XML Data Schemas, in addition, adds header’s information about the marine measurements' site, sensors and any additional necessary information. The correct header formation and the advantages of such data exchange format are analysed. Header is important for exchange between different sites from different countries as so it would be information standartization. Visual appearance of the SVG file, the source, headers and formation of the file in script are described in this paper als

Formalization of the observations of the sea level variations using XML data schemas and scalable vector graphics format

XML (Extended Markup Language) Data Schemas as the format for information exchange in graphical SVG (Scalable Vector Graphics) format is presented in the paper. SVG file format is a language for two-dimensional graphics and is based on XML. It is suggested to apply it as the advanced version of previous data exchange format TGINEX (Tide Gauge Independent Exchange Format), which contains the plain ASCII data. SVG graphics are formatted from the observations of sea level observations by the tide gauges. As an example, the formalization of data is shown on the base of the sea level observing station KLPD, which is a part of the European Sea Level Service network. XML Data Schemas, in addition, adds header’s information about the marine measurements' site, sensors and any additional necessary information. The correct header formation and the advantages of such data exchange format are analysed. Header is important for exchange between different sites from different countries as so it would be information standartization. Visual appearance of the SVG file, the source, headers and formation of the file in script are described in this paper als

The NKG2008 GPS campaign – final transformation results and a new common Nordic reference frame

The NKG 2008 GPS campaign was carried out in September 28 – October 4, 2008. The purpose was to establish a common reference frame in the Nordic- Baltic-Arctic region, and to improve and update the transformations from the latest global ITRF reference frame to the national ETRS89 realizations of the Nordic/Baltic countries. Postglacial rebound in the Fennoscandian area causes intraplate deformations up to about 10 mm/yr to the Eurasian tectonic plate which need to be taken into account in order to reach centimetre level accuracies in the transformations