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Guidance and Control - Generalized Linear Covariance Analysis and the Orbit Determination Toolkit
2:00 pm
GDC 2.402
Abstract. This talk presents a comprehensive approach to generalized covariance analysis of both batch least-squares and sequential estimators, and which is readily extended to sigma-point estimators. We review and extend in two directions the results of prior work that allowed for partitioning of the state space into "solve-for" and "consider" parameters, accounted for differences between the formal values and the true values of the measurement noise, process noise, and a priori solve-for and consider covariances, and explicitly partitioned the errors into subspaces containing only the influence of the measurement noise, process noise, and a priori solve-for and consider covariances. In the present work, we explicitly add sensitivity analysis to the prior work, and relax an implicit assumption that the batch estimator's epoch time occurs prior to the definitive span. We also apply the method to an integrated orbit and attitude problem, in which gyro and accelerometer errors, though not estimated, influence the orbit determination performance. We illustrate our results using two graphical presentations, which we call the "variance sandpile" and the "sensitivity mosaic," and we compare the linear covariance results to confidence intervals associated with ensemble statistics from a Monte Carlo analysis.
The talk will also demonstrate the use of such techniques with the Orbit Determination Toolbox (http://odtbx.sourceforge.net/ ), developed by NASA Goddard Spaceflight Center, and released publicly under a NASA Open Source Agreement.
Bio. Dr. Carpenter is a navigator at NASA Goddard Space Flight Center, where he has worked in the guidance, navigation, and control area since July of 1998. He is currently the lead navigator for the Magnetospheric Multi-Scale (MMS), due to launch in March 2015, which depends on tightly controlled formation flying among four spinning satellite in highly elliptical orbits. Before coming to NASA Goddard, Russell was at NASA Johnson Space Center from 1987 to 1998, where he worked on Shuttle and Station navigation software, GPS flight experiments, and entry guidance algorithms eventually used to land Curiosity on Mars. He has received the NASA Exceptional Service and Exceptional Achievement medals, and was the AIAA National Capital Section's Young Scientist/Engineer of the Year in 2000. Russell has over 60 publications, and received the Best Paper award at the 2011 Astrodynamics Specialists Conference. He is an Associate Fellow of the AIAA, and an Associate Editor for the Journal of the Astronautical Sciences. Russell is a graduate of the Department of Aerospace Engineering and Engineering Mechanics at The University of Texas at Austin, receiving a BS with Highest Honors in 1989, an MS in 1991, and a Ph.D. in 1996.
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