Maneuvering of Distributed Space-Borne Sensors for Optimal Interferometric Imaging Performance
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The need for high resolution, continuously sustained imaging drives the interest in space-borne, distributed aperture, interferometric (amplitude, heterodyne, or intensity correlation) systems. This paper will discuss the maneuver controls for a system of multiple space-based telescopes to secure optimal image quality. Such distributed aperture systems eff ectively measure the Fourier Transform of the collected light so that the observed wave pattern is seen in the frequency plane. This Fourier Transform representation of physical spacecraft maneuvers may be interpreted as coverage regions (discs) in the frequency plane. Superior coverage of the frequency plane, which is directly related to image quality, is investigated for imaging distant objects using interferometric techniques where apertures are distributed on multiple space-based telescopes. The corresponding cost function is based on the optimality of the spacecraft maneuvers, which in turn is based on achieving a high image quality. This study builds on previous research wherein the first-order necessary conditions (FONC) were derived. The FONC are derived for specialized rectilinear motion and expanded to incorporate varying coverage disc velocities. These linearized equations are verifi ed to be consistent with those for the constant velocity case. Next, linearized first-order necessary conditions are shown to correspond closely with the fully nonlinear case. After that, the conditions for optimal overlap of the coverage paths will be given; these conditions lead to the optimal cost based on frequency plane parameters. Finally, a heuristic approach will be used to compare diff erent frequency plane coverage strategies. An analogy to painting will be presented to demonstrate adequate signal-to-noise ratio required for a desired image quality.
Distributed Space-Borne Sensors
Optimal Imaging Performance
Sandberg, Julie (2010). Maneuvering of Distributed Space-Borne Sensors for Optimal Interferometric Imaging Performance. Master's thesis, Texas A&M University. Available electronically from