期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2002
卷号：XXXIV-3/W4
出版社：Copernicus Publications
摘要：With laser altimetry becoming increasingly accepted by the global Earth science community as a source for accurate topographic data, there is now a desire to apply this technology to large area mapping. Commonly, airborne laser systems provide data at several meter resolution and across swaths up to 1-2 km in width. Economic factors drive commercial systems to widen swaths further, but off-nadir incident angles degrade accuracy and significantly diminish the ability to penetrate dense vegetation canopies effectively limiting swath width. Higher operational altitudes (e.g., 10 km vs. 1 km) can provide up to a factor of ten increase in swath width within a selected angular range. However, higher altitude operations require significantly more laser output power, smaller divergence angles and higher beam quality to achieve smaller footprints. At NASA Goddard Space Flight Center, we have been prototyping spaceborne instrumentation and science applications of wide-swath lidar in aircraft for the last several years. This experience has led to the development of several satellite laser altimeters such as the Shuttle Laser Altimeter (SLA) and Vegetation Canopy Lidar (VCL). Technologies and methods utilized in the spaceborne environment are prototyped in the wide-swath, full-waveform airborne Laser Vegetation Imaging Sensor (LVIS). This sensor will undertake a large-area mapping mission in Brazil in June-August 2002. The sensor will use a 3 km-wide data swath and plans are underway to increase the swath width further. Spaceborne imaging applications require significantly higher effective rep-rates than airborne systems and are much less tolerant of unreliable mechanical scanning and equipment maintenance requirements. Unique scanning and ranging techniques for medium-large footprint, full-waveform mapping laser altimeters are currently under development to enable a spaceborne, wide-swath operational mapping laser altimeter capable of full-Earth mapping and dense vegetation penetration. A sample of some of the techniques being developed at NASA Goddard Space Flight Center for future airborne and spaceborne imaging lidar will be presented, including methods for achieving MHz scanning rates
