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Proceedings Paper

Design and performance of a 3D imaging photon-counting microlaser altimeter operating from aircraft cruise altitudes under day or night conditions
Author(s): John J. Degnan; Jan F. McGarry; Thomas W. Zagwodzki; Phillip W. Dabney; Jennifer Geiger; Richard Chabot; Charles Steggerda; Joseph Marzouk; Andrew Chu
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Paper Abstract

The present paper reports on the design and performance of a scanning, photon-counting laser altimeter, capable of daylight operations from aircraft cruise altitudes. In test flights, the system has successfully recorded high repetition rate returns from clouds, soils, man-made objects, vegetation, and water surfaces under full solar illumination. Following the flights, the signal was reliably extracted from the solar noise background using a Post- Detection Poisson Filtering technique. The passively Q-switched microchip Nd:YAG laser measures only 2.25 mm in length and is pumped by a single 1.2 Watt GaAs laser diode. The output is frequency-doubled to take advantage of higher detector counting efficiencies and narrower spectral filters available at 532 nm. The transmitter produces several microjoules of green energy in a subnanosecond pulse at rates approaching 10 kHz. The illuminated ground area is imaged by a 14-cm diameter, diffraction-limited, off-axis telescope onto a segmented anode photomultiplier. Each anode segment is input to one channel of fine range receiver (5-cm resolution), which records the times-of-flight of individual photons. A parallel coarse receiver provides a lower resolution (greater than 75 cm) histogram of all scatterers between the aircraft and ground and centers the fine receiver gate on the last set of returns.

Paper Details

Date Published: 23 January 2002
PDF: 10 pages
Proc. SPIE 4546, Laser Radar: Ranging and Atmospheric Lidar Techniques III, (23 January 2002); doi: 10.1117/12.453978
Show Author Affiliations
John J. Degnan, NASA Goddard Space Flight Ctr. (United States)
Jan F. McGarry, NASA Goddard Space Flight Ctr. (United States)
Thomas W. Zagwodzki, NASA Goddard Space Flight Ctr. (United States)
Phillip W. Dabney, NASA Goddard Space Flight Ctr. (United States)
Jennifer Geiger, NASA Goddard Space Flight Ctr. (United States)
Richard Chabot, Honeywell Technology Solutions Inc. (United States)
Charles Steggerda, Honeywell Technology Solutions Inc. (United States)
Joseph Marzouk, Sigma Research and Engineering Corp. (United States)
Andrew Chu, Sigma Research and Engineering Corp. (United States)


Published in SPIE Proceedings Vol. 4546:
Laser Radar: Ranging and Atmospheric Lidar Techniques III
Ulrich Schreiber; Christian Werner; Gary W. Kamerman; Upendra N. Singh, Editor(s)

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