Title: Nonlinear Estimation for Orbit Determination
By Renato Zanetti, Ph.D.
Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin
ABSTRACT: Linear estimators such as the various Kalman filter implementations, often provide subpar results in terms of accuracy and/or consistency for highly nonlinear systems. Their reliance on only a covariance matrix to represent the uncertainty and their lack of a complete approximation of the non-Gaussian evolution of the uncertainty often results in degraded accuracy; while the simplifying assumptions inevitably used to approximate nonlinear transformations of random variables might result in filter divergence. Nonlinear filters, on the other hand, rely on a complete but tractable description of the probability density function (pdf) for the uncertainty of the state of an orbiting object. Two prevalent algorithms for nonlinear estimation are the Particle Filter (PF) and the Gaussian Sum Filter (GSF), the former discretized the pdf with a finite number of random samples, while the latter approximates the pdf with a Gaussian Mixture Model. This talk will focus on the relative advantages and drawbacks of the PF and GSF and explore our current research in merging the benefits of the two. The resulting nonlinear estimation algorithms will be applied to nonlinear problems in Space Domain Awareness and Orbit Determination.
BIO: Renato Zanetti received a Laurea degree from Politecnico di Milano and a PhD from the University of Texas at Austin (UT). Renato had a ten-year professional career at Draper Laboratory and the NASA Johnson Space Center prior to returning to UT as an assistant professor of Aerospace Engineering. Renato was the principal designer of the Orbital Cygnus relative navigation system and a key member and the implementer of the Orion Exploration Flight Test 1 absolute navigation system. Renato’s work is mainly in the areas of nonlinear estimation, which he applies to uncertainty quantification and orbit determination; as well as autonomous navigation of space vehicles. Renato is a Fellow of the American Astronautical Society (AAS), an Associate Fellow of AIAA, a Senior Member IEEE, a former Chair of the AAS Space-Flight Mechanics Technical Committee, and the current chair of AIAA Astrodynamics Technical Committee.
November 19, 2021 from 3:00 p.m. to 4:00 p.m.
Attend in person projection in JH-109 or via Zoom (https://nmsu.zoom.us/j/99609263954).
If you are interested in visiting our department and giving a seminar lecture, please send an e-mail to Dr. Andreas Gross.