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Proceedings Paper

A 32x32 pixel focal plane array ladar system using chirped amplitude modulation
Author(s): Barry L. Stann; Keith Aliberti; Daniel Carothers; John Dammann; Gerard Dang; Mark M. Giza; William B. Lawler; Brian C. Redman; Deborah R. Simon
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Paper Abstract

The Army Research Laboratory is researching system architectures and components required to build a 32x32 pixel scannerless ladar breadboard. The 32x32 pixel architecture achieves ranging based on a frequency modulation/continuous wave (FM/cw) technique implemented by directly amplitude modulating a near-IR diode laser transmitter with a radio frequency (RF) subcarrier that is linearly frequency modulated (i.e. chirped amplitude modulation). The backscattered light is focused onto an array of metal-semiconductor-metal (MSM) detectors where it is detected and mixed with a delayed replica of the laser modulation signal that modulates the responsivity of each detector. The output of each detector is an intermediate frequency (IF) signal (a product of the mixing process) whose frequency is proportional to the target range. Pixel read-out is achieved using code division multiple access techniques as opposed to the usual time-multiplexed techniques to attain high effective frame rates. The raw data is captured with analog-to-digital converters and fed into a PC to demux the pixel data, compute the target ranges, and display the imagery. Last year we demonstrated system proof-of-principle for the first time and displayed an image of a scene collected in the lab that was somewhat corrupted by pixel-to-pixel cross-talk. This year we report on system modifications that reduced pixel-to-pixel cross-talk and new hardware and display codes that enable near real-time stereo display of imagery on the ladar's control computer. The results of imaging tests in the laboratory will also be presented.

Paper Details

Date Published: 13 September 2004
PDF: 9 pages
Proc. SPIE 5412, Laser Radar Technology and Applications IX, (13 September 2004); doi: 10.1117/12.542549
Show Author Affiliations
Barry L. Stann, Army Research Lab. (United States)
Keith Aliberti, Army Research Lab. (United States)
Daniel Carothers, BAE Systems (United States)
John Dammann, Army Research Lab. (United States)
Gerard Dang, Army Research Lab. (United States)
Mark M. Giza, Army Research Lab. (United States)
William B. Lawler, Army Research Lab. (United States)
Brian C. Redman, Army Research Lab. (United States)
Deborah R. Simon, Army Research Lab. (United States)


Published in SPIE Proceedings Vol. 5412:
Laser Radar Technology and Applications IX
Gary W. Kamerman; Gary W. Kamerman, Editor(s)

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