HR: 1340h
AN: C33B-0343    [Abstracts]
TI: Recent Results in ICESat Geolocation Parameter Calibration From Range Residual Analysis
AU: * Luthcke, S B
EM: Scott.B.Luthcke@nasa.gov
AF: NASA Goddard Space Flight Center, Space Geodesy Branch Code 926, Greenbelt, MD 20770 United States
AU: Rowlands, D D
AF: NASA Goddard Space Flight Center, Space Geodesy Branch Code 926, Greenbelt, MD 20770 United States
AU: Carabajal, C C
AF: NVI Inc., 7257 Hanover Pkwy Suite D, Greenbelt, MD 20770 United States
AU: Harding, D H
AF: NASA Goddard Space Flight Center, Space Geodesy Branch Code 926, Greenbelt, MD 20770 United States
AU: Williams, T A
AF: Raytheon ITSS, 1616 McCormick Drive, Landover, MD 20774 United States
AB: The Ice, Cloud and land Elevation Satellite (ICESat), launched on January 12, 2003, carries the Geoscience Laser Altimeter System (GLAS), which has a primary measurement of short-pulse laser-ranging to the Earth's surface at 1064nm wavelength at a rate of 40 pulses per second. The instrument has collected (at the time of this writing) over 540 million observations of the Earth's surface including precise elevation measurements of the ice sheets, sea ice roughness and thickness, ocean and land surface elevations and surface reflectivity. The accurate geolocation of GLAS's surface returns, the spots from which the laser energy reflects on the Earth's surface, is a critical issue in the scientific application of these data. Pointing, ranging, timing and orbit errors must be compensated to accurately geolocate the laser altimeter surface returns. Towards this end, the laser range observations can be fully exploited in an integrated residual analysis to accurately calibrate these geolocation/instrument parameters. The ICESat laser altimeter data have been simultaneously processed as direct altimetry from ocean sweeps and around-the-world scans along with dynamic crossovers in order to calibrate pointing, ranging and timing. The analysis has resolved complex time varying signal resulting from thermal variations of instrument pointing and boresite shadowing. The calibration methodology and current calibration results are discussed along with future efforts and current geolocation accuracies.
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
DE: 1241 Satellite orbits
DE: 1243 Space geodetic surveys
DE: 1294 Instruments and techniques
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting