Stanisław Schillak

The SLR stations coordinates determined from monthly arcs of lageos-1 and lageos-2 laser ranging in 1999–2001

Abstract Determination of the stations coordinates and control of their stability is one of the most important tasks of the satellite geodesy and geodynamics. The paper is a continuation of earlier works on the stability of coordinates of the laser stations in the years 1999 and 2000 and reports the position determinations of all SLR stations active in the years 1999–2001 calculated in the ITRF2000 system on the basis of observations of LAGEOS-1 and LAGEOS-2 satellites. The calculations were made using the NASA GEODYN-II orbital program. The station coordinates were determined from the monthly arcs separately for each station. RMS of all 36 month arcs was stable and equal to 17 mm on average. The final stability of the SLR stations coordinates in the three years varied from 4 mm for the most stable station to a few centimetres for less stable ones. Real shifts in the positions of the stations Tateyama and Arequipa were detected.

Stability of coordinates of the borowiec SLR station (7811) on the basis of satellite laser ranging

Abstract Borowiec satellite laser ranging station belongs to the global tracking stations network conducting continuous observations in the last decade. The accuracy of measurements has reached the level of 1–2cm for LAGEOS-1 and LAGEOS-2 satellites. The satellite laser ranging system has been generally stable in terms of the range bias since 1994. One of the important tasks of geodynamics is a determination of the station coordinates and the control of their stability. The paper presents results of determination of the position of the Borowiec SLR station (7811) calculated on the basis of the data provided by the LAGEOS-1 and LAGEOS-2 laser ranging from the results of selected 15 laser ranging stations in the International Terrestrial Reference Frame 97 system. The calculations were performed with the use of the GEODYN II program and ALPHA computers in Borowiec and Poznan Observatories. The coordinates of the Borowiec station were determined from monthly arcs for 1999, the best year in the terms of quantity and quality of Borowiec LAGEOS data. The final stability of the Borowiec SLR coordinates for all components per one year is equal to ±9 mm.

Improvement of the SLR Borowiec station position in the global network ITRF91

Abstract This paper describes briefly two station coordinates solutions, the first one computed at Space Research Centre (SRC) using tracking data from Lageos satellite, and the second one computed at European Space Operations Centre (ESOC) using tracking data from Lageos 1, ERS-1 and TOPEX/Poseidon in a multi-arc solution. In particular the solution computed for the Borowiec station in ITRF91 system is described extensively. The Borowiec station position was estimated simultaneousely, considering or not the existence of range biases, with other geophysical parameters such as: daily polar motion parameters x p , y p , ocean tide coefficients, earth gravitational constant GM, etc.