&lt;title&gt;Geo Light Imaging National Testbed (GLINT): past, present, and future&lt;/title&gt;

Ford, Stephen D.; Voelz, David G.; Gamiz, Victor L.; Storm, Susan L.; Czyzak, Stanley R.; Oldenettel, Jerry R.; Hunter, Abigail

doi:10.1117/12.364119

Cited by 10 publications

(5 citation statements)

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“…The technical aspects of Fourier telescopy stem from modern stellar interferometry, phase closure, and long-baseline interferometry [3][4][5][6] . In 1976, Aleksoff published the synthetic interferometric imaging technique for moving objects and he studied two-dimensional imaging of rotating objects 7,8 .…”

Section: Background and Development Of Fourier Telescopymentioning

confidence: 99%

“…A laser emitter is needed to provide the transmitter's coherent radiation to interfere on the object, and the geometry of transmitters array is important. For example"T" geometry is used in the GLINT design 6 . The uplink atmospheric turbulence is a significant error source of Fourier telescopy and the effects are still on research.…”

Section: Important Considerations Of Fourier Telescopymentioning

confidence: 99%

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High-resolution imaging techniques based on optical synthetic aperture

Wang

Rao

Jiang

et al. 2007

3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes

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The quest for higher angular resolution in astronomy will inevitably require the telescope with large aperture. However, the diameter of primary mirror is limited by the fabrication problems as well as the scaling laws of manufacturing costs. Optical synthetic aperture telescopes represent a promising new technology to overcome the above-mentioned problems. Three incoherent imaging techniques based on optical synthetic aperture including Fourier telescopy, Michelson interferometer and Fizeau interferometer are described in the paper. Fourier telescopy is an active imaging technique combined with the advantages of synthetic aperture measurement. Michelson interferometers measure spatial Fourier transform of objects, while Fizeau interferometers produce direct images with full instant frequency coverage. We give an overview of the basic aspects and the differences of these techniques.

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Section: Background and Development Of Fourier Telescopymentioning

confidence: 99%

Section: Important Considerations Of Fourier Telescopymentioning

confidence: 99%

High-resolution imaging techniques based on optical synthetic aperture

Wang

Rao

Jiang

et al. 2007

3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes

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“…At the narrow band filter location, directly after the collimating lens, paraxial calculations show that the maximum ray angle, β, due to a field angle, α, is given by; (1) and the maximum ray angle due to the beam divergence, θ, from a segment is;…”

Section: Collimated Chief Configurationmentioning

confidence: 99%

“…The system discussed here is for use in a geosynchronous satellite imaging experiment, GLINT, based on the Fourier Telescopy technique 1 . The concept is illustrated in Figure 1, where a 9.75 m square heliostat, consisting of a 15 × 15 square array of flat segments, acts as the primary mirror aperture for light collection.…”

Section: Introductionmentioning

confidence: 99%

A low-cost large-aperture optical receiver for remote sensing and imaging applications

Hanes¹

2003

SPIE Proceedings

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An inexpensive large aperture (10 m class) receiver for optical wavelength imaging and remote sensing applications is discussed. The design was developed for active (laser illumination) imaging of remote objects using pupil plane measurement techniques, where relatively low optical quality collecting elements can be used. The approach is also well suited for conventional imaging at lower resolutions when light collection capability is of primary importance.The approach relies on a large aperture heliostat consisting of an array of flat mirror segments, like those used in solar collector systems, to collect light from the region of interest. The heliostat segments are tilted in a manner to concentrate the light, by making the light from all segments overlap at a common point, resulting in a region of higher intensity about the size of a segment at the heliostat "focus". A smaller secondary collector, consisting of a concave mirror located at the overlap point, further concentrates the light and forms a pupil image of the heliostat. Additional optics near the pupil image collimate the light for efficient transmission though a narrow band interference filter used to reduce sky background, and focus the light onto a PMT, or other sensor, for detection. Several design approaches for the collimating optics are discussed as well as system performance and limitations.

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“…(2) One can calculate the second moment by using the presentation of the reflected field in a free space given by the…”

Section: Laser Specklementioning

confidence: 99%

Effect of turbulence on downlink and horizontal path on high-order coherence moments in Fourier telescopy system

et al. 2002

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Fourier Telescopy is an active laser-based imaging method for high-resolution imaging of dim objects in Geosynchronous (GEO) orbit. The Geo Light Imaging National Testbed (GLINT) will be build to demonstrate new powerful imaging capability. Several processes including laser speckle, atmospheric turbulence on the downlink and 1-km horizontal path, as well as Poisson shot noise can contribute to the measurement error of the Fourier phase of the object and thus degrade the reconstructed image. We investigated the impact of three processes including laser speckle, turbulence, and Poisson shot noise on the measurement error of the Fourier phase. We introduced the concept of powerin-the-bucket receiver and applied this concept to the receiver in the Fourier telescopy system. We found that the powerin-the-bucket receiver cancels the effects of turbulence on the horizontal path on the Fourier telescopy system. We evaluated variance of the real and imaginary parts of the triple product, as well as variance of the Fourier phase of the object by using a numerical simulation code. The twelfth moment of the optical filed was calculated in the presence of laser speckle, atmospheric turbulence, and Poisson shot noise. Simulation results confirmed that Fourier telescopy system is immune to the effects of turbulence on the horizontal path. It also showed that the effect of turbulence on the downlink path on the triple product is small. Laser speckle contributes strongly to the variations of the real part of the triple product and weakly to the imaginary part. Statistical properties of the triple product depend on the noise source. Poisson shot noise and laser speckle produce the main contribution to the variance of the triple product and measurement error of the object Fourier phase. Phase variance reduces with increasing the number of heliostats, number of pulses, fringe visibility, and fringe signal-to-noise ratio. For 40 heliostat receivers, 100 averaged pulses, and all considered fringe SNRs and fringe visibilities the phase variance caused by Poisson noise, laser speckle, and turbulence on the downlink path is significantly less than 0.36, which corresponds to the phase measurement accuracy of Ill 0 of the wave.

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<title>Geo Light Imaging National Testbed (GLINT): past, present, and future</title>

Cited by 10 publications

References 0 publications

High-resolution imaging techniques based on optical synthetic aperture

High-resolution imaging techniques based on optical synthetic aperture

A low-cost large-aperture optical receiver for remote sensing and imaging applications

Effect of turbulence on downlink and horizontal path on high-order coherence moments in Fourier telescopy system

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