Optical Turbulence Measurement - Investigation for Analysis of Laser Designator Spot Patterns. Phase II (Field Test). Methodology Investigation
Optical Turbulence Measurement - Investigation for Analysis of Laser Designator Spot Patterns. Phase II (Field Test). Methodology Investigation

Author: E. A. Milne

Publisher:

Published: 1986

Total Pages: 128

ISBN-13:

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This methodology investigation evaluates the feasibility of applying video instrumentation and image analysis techniques to characterize optical path turbulence for use in assessing the field performance of laser designator systems. The effort focused on adapting a (C sulon) squared path weight measurement technique, which uses a telescope mechanical slit scanner configuration for data acquisition. This effort covers the conduct of a limited field test to validate the data acquisition and data analysis process developed during Phase I of the investigation. The field test involved making (C sulon) squared measurements with the original slit scanner equipment and a video (C sulon)squared data acquisition system. Smoke was also introduced in the optical path. The amount of test data taken was limited by severe rainstorms which occurred during a normally dry season at the test site. The test results showed a correlation of 0.81 between the data collected by the two measurement systems.

Optical Turbulence Measurement - Investigations for Analysis of Laser Designator Spot Patterns
Optical Turbulence Measurement - Investigations for Analysis of Laser Designator Spot Patterns

Author: E. C. Crittenden

Publisher:

Published: 1983

Total Pages: 197

ISBN-13:

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This methodology investigation evaluates the feasibility of applying video image analysis techniques and instrumentation to characterize optical path turbulence for use in assessing the field performance of laser designator systems. The effort focused on adpating a C sub n sub 2 path weighted measurement technique developed by Dr. E. Crittenden, NPS, which uses a telescope mechanical slit scanner configuration for data acquisition. The Phase I effort presented in this report covers a theoretical analysis and empirical measurements to include a coincident path performance comparison of the scanner and a video system in a laboratory environment. Computer programs for analyzing the video data using either a real time digitizer or a digital storage oscilloscope were also developed. The results of the investigation demonstrate that the video technique can be applied to the measurement of C sub n sub 2 and a test plan to further validate the technique in a field environment is presented. (Author).

Experimental Investigations of Optical Propagation in Atmospheric Turbulence
Experimental Investigations of Optical Propagation in Atmospheric Turbulence

Author: Michael W. Fitzmaurice

Publisher:

Published: 1971

Total Pages: 196

ISBN-13:

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The pertinent theoretical background and the results of a group of experiments conducted over 0.4- and 1.17-km near-ground horizontal ranges are presented. (1) The log-amplitude variances for HeNe (0.633 μm) and CO2 (10.6 μm) laser beams were found to have a ratio of 26.8, which is in close agreement with the predictions of Rytov-based spherical-wave theory. (2) Published measurements of the saturation level of the log-amplitude variance are reviewed and several inconsistencies noted. (3) The spatial correlation function of irradiance field was measured and found to agree with theory. The degree of correlation between different frequency beams which had traversed the same optical path was also measured and compared to theory. The data exhibited an unacceptably large scatter and did not show the wavelength dependence. (4) The log-normal, Rayleigh, and Rice probability distributions are discussed in terms of their applicability to irradiance statistics. Relatively weak 10.6 μm irradiance fluctuations were found to be equally well described by the log-normal and Rice distributions; strong fluctuations obtained at 0.488 μm were clearly best described by the log-normal distribution.

Laser Doppler and Phase Doppler Measurement Techniques
Laser Doppler and Phase Doppler Measurement Techniques

Author: H.-E. Albrecht

Publisher: Springer Science & Business Media

Published: 2013-04-17

Total Pages: 741

ISBN-13: 3662051656

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Providing the first comprehensive treatment, this book covers all aspects of the laser Doppler and phase Doppler measurement techniques, including light scattering from small particles, fundamental optics, system design, signal and data processing, tracer particle generation, and applications in single and two-phase flows. The book is intended as both a reference book for more experienced users as well as an instructional book for students. It provides ample material as a basis for a lecture course on the subject and represents one of the most comprehensive treatments of the phase Doppler technique to date. The book will serve as a valuable reference book in any fluid mechanics laboratory where the laser Doppler or phase Doppler techniques are used. This work reflects the authors' long practical experience in the development of the techniques and equipment, as the many examples confirm.