HR: 1330h
AN: C32A-0430    [PDF]
TI: ICESat Precision Orbit Determination
AU: * Rim, H
EM: rim@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. Braker Ln., Suite 200, Austin, TX 78759 United States
AU: Yoon, S
EM: yoonseo@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. Braker Ln., Suite 200, Austin, TX 78759 United States
AU: Webb, C E
EM: webb@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. Braker Ln., Suite 200, Austin, TX 78759 United States
AU: Kim, Y
EM: ykim@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. Braker Ln., Suite 200, Austin, TX 78759 United States
AU: Schutz, B E
EM: schutz@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. Braker Ln., Suite 200, Austin, TX 78759 United States
AB: Following the successful launch of the Ice, Cloud and land Elevation Satellite (ICESat) on January 13, 2003, 00:45 UTC, the GPS receiver on ICESat was turned on successfully on Jan. 17, 2003. High quality GPS data were collected since then to support Precision Orbit Determination (POD) activities. ICESat carries Geoscience Laser Altimeter System (GLAS) to measure ice-sheet topography and associated temporal changes, as well as cloud and atmospheric properties. To accomplish the ICESat science objectives, the position of the GLAS instrument in space should be determined with an accuracy of 5 cm and 20 cm in radial and horizontal components, respectively. This knowledge is acquired by the POD activities using the data collected by the GPS receiver on ICESat and the ground-based satellite laser ranging (SLR) data. It has been shown from pre-launch POD studies that the gravity model error is the dominant source of ICESat orbit errors. The predicted radial orbit errors at the ICESat orbit (600 km altitude) based on pre-launch gravity models, such as TEG-4 and EGM-96, are 7-15 cm. Performance of these gravity models and the recent gravity models from GRACE on ICESat POD were evaluated. The radial orbit accuracy is approaching 1-2 cm level with the GRACE gravity model. This paper also summarizes POD activities at Center for Space Research (CSR), which is responsible to generate ICESat POD products.
DE: 1241 Satellite orbits
SC: Cryosphere [C]
MN: 2003 Fall Meeting