Eimuntas Parseliunas

The united geodetic vertical network of Latvia and Lithuania

A unified and continuous national vertical network is the back-bone for geodesy, cartography, civil engineering and global positioning. International institutions are working to reach homogenous and unified vertical datum all around the globe. Levelling evaluation on the border between Latvia and Lithuania is of particular interest. Connection between vertical networks is made in three places, so connecting lines construct the two first order levelling loops. A joined loop adjustment produces a good basis for analysis and evaluation of height connection between Latvia and Lithuania not only as neighbouring countries but also as parties to the EVRS.

LitPOS – A part of EUPOS®

Abstract LitPOS (Lithuanian Positioning System), the network of permanent reference GNSS stations, became operational in July 2007. It provides data both for real‐time and post‐processing applications. LitPOS stations cover the whole territory of Lithuania. Total number of GNSS stations is 25, therefore the integration of some stations of neighbouring countries is foreseen. It is possible on the basis of cooperation in EUPOS® project. The European Position Determination System (EUPOS® ) project is an initiative and cooperation of currently 15 Central and Eastern European countries (CEE) and two German states that build up a ground‐based European regional GNSS augmentation system with uniform standards that will cover a territory of about 10 million square kilometers. EUPOS® provides a high‐quality differential GNSS information for high‐precision positioning and navigation usable in a large field of applications. To enlarge the EUPOS® activities transcending technical realizations the project EUPOS® – Inte...

An Investigation of the Automatic Relative Gravimeters

The laboratory and field investigations of the several automatic gravimeters Scintrex CG_5 with a quartz elastic system used for the determining of gravity acceleration were performed. Research on characteristics of four gravimeters includes a five-year period. The data consists of gravimetric observations at a laboratory, on the gravimetric testline and at the points of the Lithuanian gravimetric network. The evaluation of the phenomena of the spring systems of the gravimeters was made. The stress on the estimation of the zero drift at a laboratory and field investigations was done. It was detected that zero drift does not exceed 500 μGal per day with a diapason of 200 μGal. The zero drifts per hour do not exceed 25 μGal, mostly they are under 10 μGal. According to the annual calibration results the character of the changes of the linear scale coefficients of the gravimeters were analysed too. The calibration base of 270 km length in Lithuania where the difference of the gravity acceleration of the end points is 201 mGal was used for investigations. The research showed that the biggest deviation from the unit of the linear scale coefficients does not exceed 0.013. It was noted, that the values of the linear scale coefficients of the gravimeters have a tendency to decrease. Also was noted, that the values of the linear scale coefficients have a tendency to decrease in the period between field works, and to increase - in the field works period. So the calibration of the gravimeters should be carried out before and after the field works. Based on measurements carried out during development of the Lithuanian gravimetric network, which consists of 686 gravimetric points, accuracy of gravity acceleration increments was assessed. The comparison of the observations results against the results, obtained by the LaCoste and Romberg gravimeters with metal elastic system, is presented too. The total number of common points is 51. It was stated, that the differences of the gravity accelerations measured by the different types of gravimeters at gravimetric points do not differ more than 10 μGal, therefore maximum difference of 25 μGal was received. The standard deviations of the gravity accelerations of the gravimetric points do not exceed 7 μGal. Such results show the good performance of the SCINTREX CG_5 gravimeters.

On identification of human eye retinas by the covariance analysis of their digital images

Abstract. An identification of human eye retinas by applying the covariance function and wavelet theory is presented. The estimations of the autocovariance functions of the two digital images or single image are calculated according to random functions, based on the vectors created from the digital image pixels. The estimations of the pixel’s vectors are calculated by spreading the pixel arrays of the digital images into single column. During the changing of the scale of the digital image, the wave frequencies of the colors of the single pixels are prekept, and the influence of the change of a scale in the procedures of the calculations of the covariance functions does not occur. The Red, Green, Blue (RGB) color model of the colors spectrum for the encoding of the digital images was applied. The influence of the RGB spectrum components and the tensor of colors on the estimations of the covariance functions were analyzed. The identity of the digital images is estimated by analysis of the changes of the correlation coefficient values in the corresponding diapason.

Measurement Techniques of a European Sea Level Service Site in KLAIPEDA

The technical equipment including hardware and software of European Sea Level Service (ESEAS) station KLAIPEDA (KLPD) is presented in the paper. The tide gauge Klaipeda (previous name – Memel) was established in 1811 in the east part of the Baltic Sea, at the estuaries of Curonian Lagoon. KLAIPEDA ID number at the Permanent Service of Mean Sea Level (PSMSL) is 080161. Upgrading of the station is done according to the ESEAS-RI project (Contract No EVR1-CT-2002-40025). KLPD site was equipped with a digital float tide gauge, sea-water conductivity sensor, air temperature, pressure and humidity sensors, wind speed and direction sensor and GPS receiver with antenna. The four characters ID KLPD and IERS DOMES number 10802M001 was assigned to the permanent GPS station KLAIPEDA. Tide gauge KLAIPEDA was certified as ESEAS Operational Site in 2003. It provides near real time (hourly) data to corresponding data servers. The data warehouse system is built on Gentoo Linux, with Apache2, MySQL 4.0.22 and PHP 4.3.9. The communication structure and software applications are also presented in the paper.

Features of Flexible E-Learning Modules Within Geographical Information Science for Vocational Training

The main features and general structures of two distant learning modules within geographical information science for vocational training are presented in this paper. “European Level Developments of Flexible Learning Models within Geographical Information Science (GIS) for Vocational Training (E-GIS)” was a pilot project under the Leonardo de Vinci Community action Programme on vocational training, within Geographical Information Science (GIS), to be implemented over a three year period, 2002–05. The project will be continued in 2008–2009 under the abbreviation eGIS+. The main objectives of the project is to establish co-operation between European Universities and GIS user organisations and to develop modularised courses intended for Internet based learning, establish links of communications between the partners in the project in order to disseminate and share “best practices” in different teaching situations and for different types of students. The course modules to be developed, all together, will constitute a one-year programme within GIS. This project mainly targets full time students, private and civil service employees within the European Union, but also similar categories in non-EU countries. The outcomes of the project is high level content, new net-based pedagogic method suited for accessing target groups of great diversity as regards pedagogic traditions, access to computers and bandwidth. Cooperation between the institutions will, certainly, give higher level courses than the individual institutions could possibly themselves. “Training of Lithuanian Geographic Information Infrastructure managers” is a project supported by European Union Structural Funds and National Land Service under the Ministry of Agriculture of Lithuania Republic. The main objective of the proposed geographic information e-training system is to develop and provide the modularised Spatial Information Infrastructure courses intended for on-line based learning. This mainly will target employees of civil service and private business in Lithuania and European Union. Proposed curriculum is a set of modular courses adding up to 1.5-year part-time studies in the field of Geographic Information Science and Geographic Information Infrastructure.Copyright