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Proceedings Paper

Portable daytime differential image motion sensor for atmospheric turbulence characterization
Author(s): M. Belen'kii; T. Brinkley; D. Bruns; L. DiRuscio; H. Runyeon; V. Rye; L. Angell; D. Haddock; S. Hammel; M. Lasher
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Paper Abstract

A portable differential image motion sensor (DIMS) has been developed and field demonstrated to measure the atmospheric coherence diameter, or Fried parameter, r0, both at daytime and at night. The hardware design was developed using system requirements and performance analysis. A graphical user interface (GUI) and software were developed to automatically measure r0 from collected imagery data. The DIMS system uses a short wave infrared (SWIR) camera, IR telescope with custom environmental enclosure, a rack-mount computer accessed remotely through a laptop, and an equatorial mount and tripod for accurate pointing at a selected star. The system is two-man portable. The sensor continuously measures r0 from star imagery during clear weather at any time of day or night, with an update rate of 10 minutes. A continuously nutating optical wedge moves the star image in a circle allowing automatic background subtraction. Data output is provided at the SWIR 1.6 μm wavelength and scaled to 0.55 μm and pointing at zenith. Valid r0 measurements range is from 1 cm to 20 cm (in the visible waveband). The r0 measurements over time were performed at daytime at sea level in San Diego. The largest values of r0 were observed near and after the sunset. This approach provides a straight-forward path to sea-based seeing measurements with an addition of a stabilized platform.

Paper Details

Date Published: 24 August 2010
PDF: 15 pages
Proc. SPIE 7814, Free-Space Laser Communications X, 78140J (24 August 2010); doi: 10.1117/12.860925
Show Author Affiliations
M. Belen'kii, Trex Enterprises Corp. (United States)
T. Brinkley, Trex Enterprises Corp. (United States)
D. Bruns, Trex Enterprises Corp. (United States)
L. DiRuscio, Trex Enterprises Corp. (United States)
H. Runyeon, Trex Enterprises Corp. (United States)
V. Rye, Trex Enterprises Corp. (United States)
L. Angell, Trex Enterprises Corp. (United States)
D. Haddock, Space and Naval Warfare Systems Command (United States)
S. Hammel, Space and Naval Warfare Systems Command (United States)
M. Lasher, Space and Naval Warfare Systems Command (United States)

Published in SPIE Proceedings Vol. 7814:
Free-Space Laser Communications X
Arun K. Majumdar; Christopher C. Davis, Editor(s)

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