Lietuvos valstybinis GPS tinklas

Abstract

The Zero Order GPS Network covering the territories of Estonia, Latvia and Lithuania was established in 1992, during the international EUREF BAL’92 GPS campaign. Errors of four Lithuanian Zero Order GPS Network stations with respect of reference stations in Denmark, Finland, Germany and Sweden do not exceed 9 mm in latitude and longitude and around 30 mm in ellipsoidal heights. The First Order GPS Network was designed and observed in 1992-1993 by the Geodetic Institute, Vilnius Technical University. There are 48 stations evenly spread all over the country. New System of Coordinates LKS 94 was introduced by National Lithuanian GPS Network as a reference. It has ties to the Coordinate Systems existing in the Europe and in the World. The Second Order GPS Network (consisting of 1026 stations) was measured and adjusted in 1994-1996 by Geodetic Institute as well. Average distance between stations 8 kilometers. Two stations located at the Vilnius and Siauliai Airports are included in the European Vertical GPS Reference Network (EUVN) and linked to the National Lithuanian GPS Network. Second Order GPS Network was adjusted with FILLNET and FIL600 software at the Geodetic Institute. Zero and First Order Network stations were used as a reference. Due to huge amount of data network was divided into two blocks and was adjusted separately. Error of station coordinates B, L, H with respect of closest station is less than 5 mm. National Lithuanian GPS Network errors are 10-20 times smaller than former triangulation network errors. National Lithuanian GPS Network consists of three different accuracy order stations. Their coordinates were published in the new catalogue of Lithuanian National GPS Network. Stations were divided into groups according area of location limited by map sheets in scale of 1:100 000. That means that catalogue consists of four volumes. Each station is described on separate catalogue page where GPS network order, date of observations, station name and its individual code are stated. Ellipsoidal and rectangular coordinates and ellipsoidal heights are given in LKS 94 system. Station location description, figure of horizon mask and monumentation are presented as well. National GPS Network of Lithuania is 3D reference network conforming to the contemporary coordinate transfer and accuracy requirements.