Improvements In Spaceborne Laser Altimeter Data Geolocation

For many science applications of laser altimetry, the preciselocation of the point on the Earthʹʹs surface from which the laser energy reflects is required.The laser surface return geolocation is computed from the laser altimeterʹʹs range observation in combinationwith precise knowledge of spacecraft position, instrument tracking points referenced to thespacecraft center of mass, spacecraft attitude, laser orientation, observation and attitude data timetags. An approach that simultaneously estimates the geometric and dynamic parameters of the orbit andlaser range measurement model by a combined reduction of both spacecraft tracking and laseraltimeter surface range residuals is applied to produce improved pointing, orbit and range bias solutionsand therefore improved geolocation. The data acquired by the Shuttle Laser Altimeter (SLA)-01 and 02missions constitute a valuable pathfinder data set to test algorithms in preparation for the upcoming VCL(Vegetation Canopy Lidar) and ICESat (Ice, Cloud and Elevation Satellite) missions. Results from apreliminary SLA-01 data analysis are presented along with a brief description of the methodology and itsapplication to future spaceborne missions.