Application of the Backward-Smoothing Extended Kalman Filter to Attitude Estimation and Prediction using Radar Observations

Abstract

The Lincoln Attitude Estimation System (LAES), a new tool being developed for the Space Situational Awareness Group (SSAG) at MIT Lincoln Laboratory, integrates several existing hardware and software systems, with a backward-smoothing extended Kalman filter (BSEKF). LAES is intended to determine the rotational motion of a freely tumbling spacecraft from a sequence of discrete-time radar images. The raw range-Doppler returns are collected using a ground-based sensor, which is owned and operated by the SSAG, and processed into a set of range/cross-range images. A three-dimensional geometric model is, through computer graphics procedures, displayed on top of the two-dimensional radar images, enabling an analyst to rotate (and scale in cross-range) the model in order to align it to the object's image. Therefore, the orthographic projection matrix that the computer graphics procedures computed to display the computer model, simultaneously describes the projection of the object onto the radar image plane. These measurements are essentially corrections to a nominal or baseline motion which had to be assumed in order to generate the images in the first place. Combining the reference motion, which describes the orientation of the image plane in inertial space, with the sequence of rotations describing the attitude of the spacecraft within the image plane, yields the final set of attitude measurements which are then passed to the BSEKF for processing. The existing free motion software currently in use within the Space Situational Awareness Group makes two critical assumptions: 1) that the spacecraft is a symmetric rigid body and 2) that there are no disturbance torques acting on the spacecraft during the imaging period.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Jun 01, 2009
Accession Number
ADA505330

Entities

People

  • Kyle C. Volpe

Organizations

  • Massachusetts Institute of Technology

Tags

Communities of Interest

  • Space

DTIC Thesaurus Topics

  • Accuracy
  • Air Force
  • Artificial Satellites
  • Computational Fluid Dynamics
  • Computational Science
  • Computer Graphics
  • Computer Programs
  • Computers
  • Differential Equations
  • Equations Of Motion
  • Geometry
  • Kalman Filters
  • Mathematical Filters
  • Radar
  • Radar Equipment
  • Spacecraft
  • Three Dimensional

Readers

  • Computer Vision.
  • Control Systems Engineering.
  • Radar Systems Engineering.

Technology Areas

  • Space
  • Space - Space Objects
  • Space - Spacecraft Maneuvers