Multi-transmitter aperture synthesis

Rabb, David J.; Jameson, Douglas; Stafford, Jason; Stokes, Andrew J.

doi:10.1364/oe.18.024937

Cited by 18 publications

(10 citation statements)

References 7 publications

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“…In practice, digitalholographic detection allows for the estimation of the complex field in the presence of an extended noncooperative object via speckle averaging and image sharpening algorithms or the angular diversity created by using multiple transmitters and receivers. [7][8][9][10][11][12][13][14][15][16][17][18] This versatility allows for long-range imaging, 19 three-dimensional imaging, 20 laser radar, 21 and synthetic-aperture imaging. 22 In general, the applications are abundant.…”

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confidence: 99%

Deep-turbulence wavefront sensing using digital-holographic detection in the off-axis image plane recording geometry

et al. 2016

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, "Deep-turbulence wavefront sensing using digital-holographic detection in the off-axis image plane recording geometry," Opt. Eng. Abstract. This paper develops wave-optics simulations which explore the estimation accuracy of digital-holographic detection for wavefront sensing in the presence of distributed-volume or "deep" turbulence and detection noise. Specifically, the analysis models spherical-wave propagation through varying deep-turbulence conditions along a horizontal propagation path and formulates the field-estimated Strehl ratio as a function of the diffractionlimited sampling quotient and signal-to-noise ratio. Such results will allow the reader to assess the number of pixels, pixel field of view, pixel-well depth, and read-noise standard deviation needed from a focal-plane array when using digital-holographic detection in the off-axis image plane recording geometry for deep-turbulence wavefront sensing. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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confidence: 99%

Deep-turbulence wavefront sensing using digital-holographic detection in the off-axis image plane recording geometry

et al. 2016

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“…This has recently been demonstrated in the optical regime by mechanically switching from one transmit location to the next. 70 RF MIMO techniques that use multiple simultaneous phase centers have been developed. 71 The increase in effective aperture diameter D eff for a synthetic aperture imaging ladar, with the real aperture large enough to be taken into account, is shown in Eq.…”

Section: Flash Aperture Synthesismentioning

confidence: 99%

Review of ladar: a historic, yet emerging, sensor technology with rich phenomenology

McManamon¹

2012

Opt. Eng

202

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Abstract. Ladar is becoming more prominent due to the maturation of its component technologies, especially lasers. There are many forms of ladar. There is simple two-dimensional (2-D) ladar, similar to a passive electro-optic sensor, but with controlled illumination and the ability to see at night even at short wavelengths. There is three-dimensional (3-D) ladar, with angle/angle/range information. 3-D images are very powerful because shape is an invariant. 3-D images can be easily rotated to various perspectives. You can add gray scale or color, just like passive, or 2-D ladar, imaging. You can add precise velocity measurement, including vibrations. Ladar generates orders of magnitude higher frequency change then microwave radar for velocity measurement, because frequency change is proportional to one over the wavelength. Orders of magnitude higher frequency change means you can measure a given velocity orders of magnitude quicker, in many cases making an accurate measurement possible. Polarization can be used. With an active sensor you control both the illumination and the reception, so you can pattern the illumination. Also, because ladar can use narrow band illumination it is easier to easier to coherently combine sub-aperture images to obtain the higher resolution of an array.

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“…One such technique that is receiving considerable attention is digital holography. 4,5 In this approach low frame rate cameras are used to record the spatial fringe pattern produced by interfering the received wavefront with a local oscillator (reference beam). The local oscillator is at the same frequency of the illumination wavelength so as not to produce temporal motion of the fringes.…”

Section: Coherent Approaches To Electric Field Measurementmentioning

confidence: 99%

“…An approach to overcoming these issues has been to use image sharpening techniques in post-detection processing. 4,5 Hence, this technique uses hardware that is easier to implement at the expense of complex post detection processing. Such processing is a subject of on-going research…”

Section: Coherent Approaches To Electric Field Measurementmentioning

confidence: 99%

Conformal apertures: concepts and requirements

Watson

2011

SPIE Proceedings

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Architectures for a conformal electro-optical aperture that is based on a collection of subapertures are considered. Such architectures have different requirements for passive and active systems. In this paper we consider requirements for active systems. In particular we consider concepts for measuring the scattered illumination field at the subaperture. We discuss requirements on the subapertures, such as phasing and steering.

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Multi-transmitter aperture synthesis

Cited by 18 publications

References 7 publications

Deep-turbulence wavefront sensing using digital-holographic detection in the off-axis image plane recording geometry

Deep-turbulence wavefront sensing using digital-holographic detection in the off-axis image plane recording geometry

Review of ladar: a historic, yet emerging, sensor technology with rich phenomenology

Conformal apertures: concepts and requirements

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