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NASA/NOAA: Airborne Topographic Mapper

NASA has developed an airborne laser-based topographic survey instrument based on its Airborne Oceanographic Lidar (AOL). The AOL instrument was conceived in 1975 as an airborne test-bed for new applications of laser remote sensing and the original instrument was built in 1977 under a joint program sponsored by NASA and NOAA. The purpose of the joint interagency program was to investigate the potential for the airborne laser sensor in the areas of altimetry, hydrography, and fluorosensing. The AOL has been in operation since 1977 but the instrument has undergone considerable modifications including several major redesigns during this period. Consequently, it has remained a state-of-the-art airborne laser remote sensing instrument. The topographic mapping and ocean fluorosensing functions of the AOL were separated in 1994 when the old hardware was replaced by two new systems, with the topographic subsystems referred to as the Airborne Topographic Mapper (ATM). The AOL and the ATM are currently operated by the Observational Science Branch of NASA's Laboratory for Hydrospheric Processes.

In the research field, a major task of the AOL/ATM since 1991 has been the measurement of the Greenland ice sheet with the goal of determining changes in the ice sheet elevation. Other uses have included verification of satellite altimeters, and the measurement of sea-ice thickness. The system often flies in conjunction with other instruments, and has been used to measure sea-surface elevation and ocean wave characteristics. The ATM is also providing data in support of NASA's Solid Earth Science programs for which ATM data is acquired and processed by the Observational Science Branch within the Laboratory for Hydrospheric Processes.

Since 1995 NASA has been using the ATM in conjunction with NOAA's Coastal Services Center to conduct various beach mapping missions. The Airborne LIDAR Assessment of Coastal Erosion (ALACE) project is the research arm of this initiative. Here protocols for collecting and processing the beach survey data are being developed and scientific research using the laser data is being conducted. The BeachMap project is the public outreach and data product distribution arm of laser beach mapping. NOAA intends to work with the various state agencies to present the shoreline data in a format that is useful for coastal resource managers. This initiative is an excellent example of how the speed, accuracy, density and low cost of airborne laser data can help to create valuable mapping products previously too expensive to consider. Currently NOAA uses a revised design of the ATM, the ATM-2, for its beach mapping work. An excellent summary of this system and its operation, including a technical description of the laser sensor, can be found at New Technologies for Coastal Mapping . More technical details and specifications can be found on the Airborne Topographic Mapper (ATM) II Specifications page. NASA also has results online from other ATM beach mapping projects.

The USGS is also a partner in the coastal survey projects and has a web site dedicated to Coastal Lidar Mapping. Their site includes a discussion on the results of surveys done on the west coast of the US with NASA's ATM system, including a brief description of the system, and a interactive display of the lidar data.

The various NASA, NOAA and USGS sites listed above are all cross-linked and well integrated. They contain a great deal of information about the technology and the applications of airborne laser mapping with a strong emphasis on coastal engineering. While the actual instruments are designed based on research not commercial priorities, it is well worth reading about the background, system designs, field survey results and future plans of these research groups.

The commercialisation of the NASA ATM technology is being carried out by the Houston Advanced Research Institute (HARC) in conjunction with TerraPoint LLC, a division of Transamerica.

NASA Laser Remote Sensing Branch

The Laser Remote Sensing Branch of the Laboratory for Terrestrial Physics at Goddard Space Flight Center (GSFC) is responsible for developing advanced laser and electro-optic instruments for various NASA missions. The sensors developed by the Branch are used as laboratory test-beds and ground-based measurement systems, and are flown on numerous NASA aircraft and in space as experimental or scientific payloads. To date, laser instruments have been developed for remote sensing studies of the Earth, Moon, and Mars. Other activities include analysis and modelling of the measurement approach and instrument performance as well as breadboard studies of instrument systems.

The Laser Altimeter Processing Facility (LAPF) at Goddard is dedicated to processing and distributing data products acquired by experimental airborne and spaceborne laser altimeters developed within within the Laboratory for Terrestrial Physics. The LAPF is developing algorithms and methodologies for processing experimental surface lidar and wide-swath scanning systems. The data products being generated are therefore evolving, yielding topography measurements of increasing accuracy. Standard data products from three instruments are being produced under the auspices of the LAPF: the airborne SLICER (Scanning Lidar Imager of Canopies by Echo Recovery) and RASCAL - RAster SCanning Airborne Lidar instruments and the spaceborne series of Shuttle Laser Altimeter (SLA) instruments.

Also of interest on the research front is Earth System Science Pathfinder Project a component of the Earth Science Enterprise (ESE) that addresses unique, specific, highly-focused mission requirements in Earth science research. This program includes the VCL: The Vegetation Canopy Lidar Mission which is a satellite-based topographic lidar instrument.