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Proceedings Paper

Phase closure and object reconstruction algorithm for Fourier telescopy applied to fast-moving targets
Author(s): Brett Spivey; James Stapp; David Sandler
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Paper Abstract

Fourier Telescopy (FT) is an active imaging method which interferes spatially diverse, frequency-encoded laser beams on a distant target, and records a time history of the reflected intensity measured by a single photodetector on a large receiver. FT has been studied extensively for imaging Geostationary objects, using high-energy pulsed lasers to project triplets of laser beams, by gradually stepping over time through the multitude of u,v-plane baselines required for accurate object reconstruction. Phase closure among the received triplets plays a key role in canceling out random atmospheric phase errors between laser beams. A new method has been devised to apply FT to rapidly moving targets, such as LEO space objects. In order to implement the thousands of baselines in a short engagement time, approximately 20 continuous-wave laser beams are simultaneously broadcast, and the baseline configurations are rapidly changed through a dynamic optical element. In order to eliminate unknown atmospheric errors, a new type of global phase closure has been developed, which allows image reconstruction from the time history of measured total reflected intensity, originating from the complex 20-beam interference patterns. In this paper, we summarize the new FT LEO method, and give a detailed derivation of the phase closure and image reconstruction algorithms that will lead to ultra-high resolution images of fast-moving space objects.

Paper Details

Date Published: 8 September 2006
PDF: 16 pages
Proc. SPIE 6307, Unconventional Imaging II, 630702 (8 September 2006); doi: 10.1117/12.682179
Show Author Affiliations
Brett Spivey, Quexta (United States)
James Stapp, Trex Enterprises Corp. (United States)
David Sandler, Trex Enterprises Corp. (United States)


Published in SPIE Proceedings Vol. 6307:
Unconventional Imaging II
Victor L. Gamiz; Paul S. Idell; Marija S. Strojnik, Editor(s)

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