Accession Number : ADA335600

Title :   Orbit Estimation Using Track Compression and Least Squares Differential Correction

Descriptive Note : Master's thesis

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Chioma, Vincent J.

PDF Url : ADA335600

Report Date : DEC 1997

Pagination or Media Count : 152

Abstract : This thesis develops two methods of compressing a track of radar observations of a satellite into a single state vector and associated covariance matrix, and a method of estimating orbits using results from multiple tracks. The track compression uses least squares differential correction to determine a state vector at the central observation time. The resulting state vectors and covariance matrices are then used to estimate the satellite's orbit, also using least squares differential correction. Numerical integration using two-body, J2 and an atmospheric drag model is used to represent the dynamics. This orbit estimation produces a state vector which includes the ballistic coefficient, as well as an associated covariance matrix. Finally, a one-fiftieth scale demonstration of the full AFSPC catalog of satellites and debris is conducted to demonstrate the improvement in accuracy over current practice which results. The truth model includes J2 zonal harmonic effects and an atmospheric drag model. This demonstration shows that the orbits of 90% of the entire catalog of objects can be estimated with sufficient accuracy to allow position determination within one kilometer after only two days of tracking. Within four days, most satellite positions are determined within fifty meters.

Descriptors :   *EARTH ORBITS, *LEAST SQUARES METHOD, *ARTIFICIAL SATELLITES, EQUATIONS OF MOTION, MAXIMUM LIKELIHOOD ESTIMATION, TAYLORS SERIES, MATRICES(MATHEMATICS), RADAR TRACKING, THESES, NUMERICAL INTEGRATION, POSITION FINDING, AERODYNAMIC DRAG, VECTOR ANALYSIS, FLIGHT PATHS, SPACECRAFT TRAJECTORIES.

Subject Categories : Spacecraft Trajectories and Reentry
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE