LEOSLR - Improved kHz-SLR Tracking Techniques and Orbit Quality Analysis for LEO-Missions

The selection of the GOCE mission to be the first Core Mission of ESA’s Living Planet Programme as well as the launch of the LEO (Low Earth Orbiters) gravity missions CHAMP and GRACE, accentuated the urgent need of the geoscientific market for a precise global gravity field. The fact that all these satellites carry laser retro-reflectors on-board emphasizes the importance of Satellite Laser Ranging (SLR) as an independent external tracking instrument. However, it is a big challenge for the laser network to track low orbiting satellites in general, and especially the GOCE spacecraft at an altitude of about 250 km. Therefore, it is assumed that some of the worlds leading SLR stations will have to be technologically upgraded in order to cope with this situation. This project, which is under the lead of the Space Research Institute of the Austrian Academy of Sciences, aims at an implementation of • optimized kHz-SLR tracking techniques for LEO-tracking; • quality assessment tools for LEO orbits and Quick-Look gravity field solutions. A number of technological upgrades of the Lustbühel Laser Observatory will be performed in order to achieve a faster target acquisition, to increase the amount of data per satellite pass and to increase the accuracy of normal point observations as well as the overall system stability. Based on the tracking of LEOs, an orbit quality assessment procedure will be applied, which comprises comparisons of kinematic ranges and dynamic arcs derived from SLR data with GPS orbits. The Quick-Look gravity field analysis solutions, performed in the framework of the project “GOCE High-Level Processing Facility (HPF)”, are also subject to these independent quality assessment methods.