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Estimation of the elastic earth parameters using SLR data for the low satellites STARLETTE and STELLA

Rutkowska M., Jagoda M.

Acta Geophysica

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2012

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Vol. 60, no. 4

1213-1223

EN

In this paper we present estimated values for the global elastic parameters (k2, k3) and (h2, l2) derived from the analysis of Satellite Laser Ranging (SLR) data. We analyse SLR data for two low satellites, STARLETTE and STELLA, collected over a period of two years, from 1 January 2005 to 1 January 2007, from 18 globally distributed ground stations. We carry out a sequential analysis for the two satellites jointly, and study the stability of the estimates as a function of the length of the data set used. The adjusted final values of (k2, k3) and (h2, l2) for STARLETTE and STELLA are compared to, and are largely found to support, the estimates we previously published based on data for two high satellites LAGEOS 1 and LAGEOS 2. A major discrepancy between the two solutions was only found for the Shida number l2.

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Estimation of the elastic earth parameters using the SLR LAGEOS 1 and LAGEOS 2 data

Rutkowska M., Jagoda M.

Acta Geophysica

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2010

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Vol. 58, no. 4

705-716

EN

We present results for the global elastic parameters (k 2, k 3) and (h 2, l 2) derived from the analysis of Satellite Laser Ranging (SLR) data. The SLR data for two satellites, LAGEOS 1 and LAGEOS 2, collected over a period of two years, from 1 January 2005 to 1 January 2007, from 18 globally distributed ground stations are analyzed using different approaches. The analysis is performed for the two satellites jointly, and the four elastic parameters are estimated. We carry out a sequential analysis and study the stability of the estimates as a function of the length of the data set used. The adjusted final values for k 2 (0.3011±0.0001) and k 3 (0.0896±0.0037) and those for h 2 (0.6146±0.0006) and l 2 (0.0883±0.0003) for LAGEOS 1 and LAGEOS 2 tracking data are compared to the estimates derived in other studies.

3

Determination of the GOCE satellite orbit sensitivity under the influence of perturbing forces

Bobojć A., Drożyner A.

Artificial Satellites : Journal of Planetary Geodesy

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2007

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Vol. 42, No. 2

121--128

EN

The work contains the results of research into the simulated orbit of the GOCE satellite. Satellite accelerations due to atmospheric drag, the gravitation of the Moon, the gravitation of the Sun, the gravitation of the planets, the Earth tides, the ocean tides, the solar radiation pressure, the reflected solar radiation pressure and the relativity effects were computed. Besides the reference orbit (i.e. the orbit as close as possible to the GOCE planned orbit), the various variants of the satellite orbit (called the modified reference orbits – with different motion models) were obtained. The motion models contained the forces determining the satellite motion. For the orbital computations, the Cowell numerical integration of the eighth order was used. The geopotential was described by means of the EGM96 model. In order to obtain the influence of the aforementioned forces on the GOCE orbit, the percentage contributions of the accelerations due to these forces in the sum of all accelerations were computed. The maximum values of the mentioned accelerations were computed for the GOCE orbit variant with the motion model containing all given above forces. These values were compared with the measurement error of the linear accelerations by the GOCE satellite control system. The comparison between the reference orbit and the computed variants of the orbit was performed. In order to perform this comparison, the distances between the satellite position in the reference orbit and the satellite position in the given modified reference orbit (i.e. in a given orbit variant) were determined. These distances were compared with the total error of the GOCE satellite position determination. The orbital arc lengths, for which the selected forces can be neglected in the satellite motion model, were determined from this comparison. For these orbital arc lengths, the distance between the satellite position in the reference orbit and the satellite position in the given modified reference orbit is less or equal to the total error of the GOCE satellite position determination.