B029-02
GEDI Geolocation Parameter Calibration and Geolocation Performance
Tuesday, 8 December 2020: 20:34
Virtual
Scott B Luthcke, NASA Goddard Space Flight Center, Geodesy and Geophysics Lab, Greenbelt, MD, United States, Taylor Thomas, Emergent Space Technologies, Laurel, MD, United States, Terry Pennington, KBRwyle, Greenbelt, United States, Timothy William Rebold, Emergent Space Technologies, Sterling, VA, United States, David D Rowlands, NASA Goddard Space Flight Center, Greenbelt, MD, United States, Joseph B Nicholas, Emergent Space Technologies, Inc @ NASA GSFC Geodesy and Geophysics Lab, Greenbelt, MD, United States and Xu Yang, KBRwyle, Greenbelt, MD, United States
Abstract:
The Global Ecosystem Dynamics Investigation (GEDI) instrument was launched to the International Space Station (ISS) on Dec. 5
th, 2018. The latest in NASA’s spaceborne laser altimetry, this mission will deliver annually over ten billion new observations of the Earth’s surface elevation and surface structure for ecosystem, geodetic, and multi-disciplinary science. The accurate geolocation of the laser altimeter surface returns, the spots from which the laser energy reflects on the Earth’s surface, is critical to the scientific application of these data. The GEDI geolocation requirement of 10 meters horizontal is quite challenging given the many issues arising from a geodetic instrument implemented on the ISS.
To achieve the mission geolocation performance requirement, pointing, ranging, timing and positioning errors must be compensated to accurately geolocate the laser altimeter surface returns. Towards this end, the laser range observations are fully exploited in an integrated residual analysis to calibrate these geolocation parameters. Detailed altimeter measurement models and the reduction of both direct altimeter range observations, as well as multi-beam crossover altimeter observations are used for the geolocation parameter calibration. Here we provide an overview of the GEDI geolocation algorithms, implementation, and modeling standards. We present the resultant time dependent geolocation parameter calibration, and the resultant geolocation performance. We characterize the components of the errors as well as the overall geolocation error in comparison to the mission requirements. In addition, we discuss future improvements and expected geolocation performance.
