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).

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.

Experiments for Laser Beam Propagation Through Optical Turbulence
Experiments for Laser Beam Propagation Through Optical Turbulence

Author: Angel Fernandez

Publisher:

Published: 2016

Total Pages: 0

ISBN-13:

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Atmospheric turbulence, generated by a differential temperature between the Earth's surface and the atmosphere, causes effects on optical waves that have been of great interest to scientists for many years. Wave front distortions in the optical wave induced by atmospheric turbulence result in a spreading of the beam beyond that due to pure diffraction, random variations of the position of the beam centroid, and a random redistribution of the beam energy within a cross section of the beam leading to irradiance fluctuations. Those effects have far-reaching consequences on astronomical imaging, free space optics (FSO) communications, remote sensing, laser satellite communication, astronomical imaging, adaptive optics, target designation, hyperspectral LiDAR, and other applications that require the transmission of optical waves through the atmosphere. Throughout this thesis, we introduce a globally concept of turbulence, focusing in atmospheric turbulence.Diverse experiments have been carried out, for instance, the propagation of two parallel thin beams under geometrical optics condition for studying the parameters of optical turbulence, and besides, the same optical configuration was used to investigate the best sampling rate for optical turbulence. Furthermore, we have measured evapotranspiration by remote sensing, in which we have heeded the fluctuations of the refractive index through the intensities of the turbulence. Finally, experiments which involve a new beam are also developed, such as phase-flipped Gaussian beam. This beam shows an experimental reduction on its irradiance fluctuations induced by the turbulence, which means that it has a high performance in optical communications. The experimental reduction aforementioned is proved through the comparison with the theory developed.