meetings - Space Flight Mechanics Committee

10:45 AAS The Unscented Semi-analytical Kalman Filter
13-281 Weijun Huang, Albany, CA; Paul Cefola, University at Buffalo, State University of
New York
An effective catalog maintenance strategy is needed to keep track of all the space objects
including active and inactive satellites, rocket bodies, and smaller space debris. This paper
designs and proposes the Unscented Semianalytical Kalman Filter (USKF) for rapid orbit
tracking. The USKF combines the Draper Semianalytic Satellite Theory (DSST) with the
Unscented Kalman Filter. Since the mean equinoctial elements are chosen as the filter
solve-for variables, the USKF is expected to be more effective than the existing orbit
tracking algorithms. Both simulated and real observation data will be used to test the
performance of the USKF.
11:05 AAS Applications of Unscented and Quadrature Consider Filters using a Modified
13-283 Joseph Formulation
Kyle DeMars, Air Force Research Laboratory; Renato Zanetti, Draper Laboratory
Consider filters provide an approach for accounting for the effects of uncertain parameters
within the measurement function when performing state updates. The consider parameters
are the parameters which yield statistically important effects in updating the state of a
system, but for which improved estimates are not required, e.g. sensor biases. This paper
develops a general covariance update equation via a Joseph formulation that is valid when
considering nonlinear measurements and studies the properties of the developed method.
Simulation studies for both linear and nonlinear measurements are considered and
compared for both unscented and quadrature formulations of the filtering step.
11:25 AAS Drag Coefficient Modeling for GRACE using Direct Simulation Monte Carlo
13-284 Piyush Mehta, University of Kansas; Craig McLaughlin, University of Kansas
The drag coefficient of a satellite in LEO is a strong function of energy-accommodation,
gas-surface interaction, attitude, satellite geometry, spacecraft relative velocity, atmospheric
composition, atmospheric temperature, and spacecraft surface properties. The Direct
Simulation Monte Carlo (DSMC) code, DS3V, is used to develop a drag coefficient model
for GRACE. The code is validated with the analytical solution for the drag coefficient of a
sphere and cylinder and drag coefficients derived for GRACE using a flat plate model. The
energy-accommodation model assumes Maxwellian (diffuse) gas-surface interactions.
23 rd AAS / AIAA Space Flight Mechanics Meeting Page 43