Doyle Hall (Boeing LTS Inc.), Brandoch Calef (Boeing LTS), Keith Knox (Boeing LTS), Mark Bolden (Air Force Research Laboratory), Paul Kervin (Air Force Research Laboratory)
Keywords: NROC, Non-resolved Object Characterization
Abstract:
Time-resolved photometric measurements provide a means of constraining the attitude and/or shape of on-orbit objects that are too small or distant to be imaged by ground-based optical or radar facilities. At the most general level, a detailed inversion of photometric data to determine attitude and shape entails the solution of a multivariate numerical optimization problem involving two classes of variables: attitude and body parameters. Attitude parameters specify the object orientation at the times of the observations and provide a means to convert between the inertial reference frame and the body-centered and body-fixed reference frame. Body or “shape” parameters provide the information required to calculate the flux reflected from the object within the body reference frame. Our analysis indicates that the most basic requirement for the analysis is an extensive set of photometric observations, ideally gathered from multiple perspectives and under multiple illumination conditions. Given such a rich data-set, a complete attitude/shape inversion analysis requires supercomputer resources to address in a timely fashion, even for relatively simple convex objects. The basic reason for this is that the inversion approach requires solving for a large number object attitude and shape parameters simultaneously. A significantly more computationally efficient means of addressing the problem would be to separate the attitude and body parameter determination analyses, if at all possible. In this regard, we present a variety of theoretical approaches for both shape-independent attitude analysis and attitude-independent shape analysis for non-resolvable objects.
Date of Conference: September 12-15, 2007
Track: Non-resolved Object Characterization