University of Colorado Boulder ASEN 5070: Statistical Orbit Determination I Fall 2014 Professor Brandon A. Jones Lecture 38: Information Filter
University of Colorado Boulder Homework 11 due on Friday ◦ Sample solutions posted online Lecture quiz due by 5pm on Friday Exam 3 Posted On Friday ◦ In-class Students: Due December 12 by 5pm ◦ CAETE Students: Due 11:59pm (Mountain) on 12/14 Final Project Due December 15 by noon 2
University of Colorado Boulder 3 Information Filter
University of Colorado Boulder 4 Well, we know that the CKF has problems… Negative Values
University of Colorado Boulder 5 How about the Joseph formulation of the measurement update? Negative Values
University of Colorado Boulder 6 How about the EKF?
University of Colorado Boulder 7 How about the Potter square-root filter?
University of Colorado Boulder 8 Based on the class so far, what are we unable to do with Potter that we can do with the CKF?
University of Colorado Boulder Time Update 9 Measurement Update:
University of Colorado Boulder 10 What if we go back to the minimum variance?
University of Colorado Boulder 11 If I don’t want to invert the information matrix, do I have another option?
University of Colorado Boulder Well, that was easy. What about the time update? 12
University of Colorado Boulder What can we do to simplify this? 13 (Assume Q k non-singular)
University of Colorado Boulder Require that Q k be non-singular Do not need to invert the information matrix 14 Still need to maintain information matrix separate from D !
University of Colorado Boulder From the time update of the information matrix: 15
University of Colorado Boulder 16 Can I initialize the filter with an infinite a priori state covariance matrix? What happens if we have very accurate measurements?
University of Colorado Boulder Once the information matrix is positive definite: 17
University of Colorado Boulder 18 Provides a more numerically stable solution Stability equals that of the Batch, but in a sequential implementation Don’t need to generate state/covariance until needed Square-root information filter (SRIF) ◦ Refined through extensive use in POD ◦ Includes smoothing capabilities
University of Colorado Boulder 19 Information Filter with Bierman’s Problem
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University of Colorado Boulder 23 FCQs