Tracking turbulence-induced tilt errors with shared and adjacent apertures*†

Greenwood, Darryl P.

doi:10.1364/josa.67.000282

Cited by 16 publications

(3 citation statements)

References 4 publications

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“…The condition of Eq. (13) implies that the beam radius at the PS is much greater than the sending aperture, i.e., W 1 ≫ D. In terms of optical tracking, this situation corresponds to a strong on-axis aperture mismatch and leads to a decorrelation between the measured AoA and the angular deviation of the emitted beam [26]. Furthermore, the point-ahead angle, which is induced by the satellites' motions, strengthens this decorrelation [27].…”

Section: Effect On Optical Trackingmentioning

confidence: 99%

Atmospheric occultation of optical intersatellite links: coherence loss and related parameters

Perlot

2009

Appl. Opt.

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The Rytov theory is applied to find the wave structure function of a laser beam transmitted from one satellite to another and propagating through the turbulent atmosphere. The phase-screen approximation is used. Taking into account refractive-index anisotropy, outer scale, and atmospheric mean-refraction defocusing, we provide expressions of the wave structure function for a spherical wave. The width and time of coherence at the receiver are evaluated. Expression for the beam spread is found using the extended Huygens-Fresnel principle, and beam wander is assessed. Beam wander occurs only for very narrow beams. Links involving low-Earth-orbit and geosynchronous satellites are studied as examples. Finally, conditions where optical tracking is perturbed by the atmosphere are examined.

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Section: Effect On Optical Trackingmentioning

confidence: 99%

Atmospheric occultation of optical intersatellite links: coherence loss and related parameters

Perlot

2009

Appl. Opt.

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“…Since the design uses a single tracker to point the aperture, the effects of pupil mismatch first presented by Fried and Greenwood, are evaluated. [13][14][15] Wave optics simulations allow for a complete evaluation of sensitivity and combined effects, including beam quality, platform jitter, adaptive optics, and thermal blooming. The wave optics simulations use a medianatmosphere for absorption and scattering levels with two turbulence levels.…”

Section: Introductionmentioning

confidence: 99%

Comparison of coherent and incoherent laser beam combination for tactical engagements

et al. 2012

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Abstract. The performance of a multibeam laser system is evaluated for coherent and incoherent beam combination under tactical scenarios. For direct comparison, identical aperture geometries are used for both, coherent or incoherent, combination methods. The analysis assumes a multilaser source coupled with a conventional 0.32 m diameter, on-axis, beam director. Parametric analysis includes variations over residual errors, beam quality, atmospheric effects, and scenario geometry. Analytical solutions from previous results are used to evaluate performance for the vacuum case, providing an upper bound on performance and a backdrop for organizing the multitude of effects as they are analyzed. Wave optics simulations are used for total system performance. Each laser in the array has a wavelength of 1.07 μm, 10 kW (25 kW) output power, and Gaussian exitance profile. Both tracking and full-aperture adaptive optics are modeled. Three tactical engagement geometries, air to surface, surface to air, and surface to surface, are evaluated for slant ranges from 2.5 to 10 km. Two near-median atmospheric profiles were selected based upon worldwide climatological data. The performance metric used is beam propagation efficiency for circular target diameters of 5 and 10 cm. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

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“…Isoplanatism takes on a fundamental role in the field of atmospheric optics, however, where its effects are apparent and of considerable importance. [1][2][3][4][5][6][7][8][9] For instance, even with a perfect ground-based adaptive optics telescope it is impossible to form a diffraction-limited image of an angularly extended astronomical body.1-3 Optical rays from different regions of the body will pass through distinct sections of the atmosphere, each of which has its own optical transfer function. Fundamentally, the telescope cannot correct for these multiple transfer functions simultaneously, and a distorted image will result.…”

Section: Introductionmentioning

confidence: 99%

Stellar scintillation technique for the measurement of tilt anisoplanatism

Winick

Marquis

1988

J. Opt. Soc. Am. A

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The significance of tilt anisoplanatism is established, and a measurement theory, based on aperture-averaging intensity scintillation, is developed. The theory is a direct extention of the technique currently used to determine the isoplanatic angle as defined by Fried [J. Opt. Soc. am. 72, 52 (1982)]. By using this theory, a physically realizable binary aperture-weighting function is derived for a particular case of interest. It is noted that direct quantitative measurements of tilt anisoplanatism can also be made, under specific circumstances, by tracking the relative centroid motion of a binary star pair. Thus independent verification of the remote-sensing theory for tilt anisoplanatism, based on aperture-averaging scintillation measurements, should be possible.

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Tracking turbulence-induced tilt errors with shared and adjacent apertures*†

Cited by 16 publications

References 4 publications

Atmospheric occultation of optical intersatellite links: coherence loss and related parameters

Atmospheric occultation of optical intersatellite links: coherence loss and related parameters

Comparison of coherent and incoherent laser beam combination for tactical engagements

Stellar scintillation technique for the measurement of tilt anisoplanatism

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