Estimated Satellite Cluster Elements in Near Circular Orbit
Abstract
Arraying satellites into clusters has been under consideration for commercial communications applications. Stationing these satellites in a restricted section of an orbit allows for in-orbit spares to replace satellites as they fail. An additional benefit to military planners increased wartime system survivability. A proposed use of such a satellite cluster would be a space based radar. In order to form a cohesive image of the radar return, the relative positions of the satellites need to be known to within one quarter of the radar wavelength. For the purposes of this thesis, 25 meters is considered sufficiently accurate. This thesis investigated the performance of an on-board filter algorithm in estimating the relative positions of each element in a ten satellite orbital cluster. The on-board estimator is the U-D covariance factorization version of the Kalman filter with dynamics based on the Clohessy- Wiltshire equations. Performance is measured by comparing the square root of the position covariance eigenvalues to the magnitude of true position errors. True errors are also compared to minimum accuracy requirements. Filter tuning is limited to adjusting the diagonal entries of the dynamics noise matrix. Test cases include: perfect initial conditions with perfect range data; and perfect initial conditions with noise corrupted measurements. The position errors were well within the accuracy requirements for all test cases. Theses. (edc)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1988
- Accession Number
- ADA202938
Entities
People
- Michael L. Ward
Organizations
- Air Force Institute of Technology