Abstract

The Geoscience Laser Ranging System (GLRS), a spaceborne picosecond laser ranging and altimetry system, has been proposed as an instrument on the Earth Observing System (EOS), an unmanned remote sensing platform to be launched by NASA in the 1990s. In the ranging mode, the GLRS instrument measures the times-of-flight between the spacecraft and an array of ground-based retroreflectors. The total data set of individual range measurements can be processed to yield the 3-D relative coordinates of each target with centimeter accuracies. By revisiting the target sites at periodic intervals on subsequent orbits, relative motions can be observed. Applications include the measurement of tectonic plate or ice sheet velocities, crustal deformation, ground subsidence caused by oil or water withdrawal, large scale engineering projects (highways, pipelines, etc.), and survey densification. In the altimetry mode, GLRS measures time-of-flight to an underlying diffuse scattering surface. The altimetry capabilities of GLRS are greatly enhanced by its unique ability to provide centimeter accuracy updates to its own orbital ephemeris while retroranging. Potential applications include measurement of terrain profiles, biomass (tree canopy heights), ice-sheet thickness, marine geoid, atmospheric surface pressure over oceans, and oceanographic features (wave height, surface roughness, etc.). The presentation reviews the design, applications, simulations, hardware status, and instrument heritage of the GLRS system.

© 1986 Optical Society of America