Jeroen L. Geeraert, Colorado Center for Astrodynamics Research – University of Colorado, Jay W. McMahon, Colorado Center for Astrodynamics Research – University of Colorado
Keywords: Relative Orbit Determination, Geostationary Satellites
Abstract:
The location of operational space assets around the Earth is still of primary concern in the SSA community due to the ever increasing density of man-made objects and potential for collisions. In this paper we demonstrate using the double differenced measurements of time difference of arrival (TDOA) and frequency difference of arrival (FDOA) for relative orbit determination of multiple satellites. A close proximity two-spacecraft formation with bounded orbits is presented to demonstrate the TDOA and FDOA OD capabilities. Two scenarios are examined, the first is with the chief satellite assumed to have perfectly known state knowledge, and the second assumes some small uncertainty on the chief satellite. In the first scenario a square-root unscented Kalman filter is used to estimate the state of the deputy about the chief, and in the second scenario the deputy satellite is estimated while the uncertainty of the chief satellite is considered using the square-root unscented Schmidt-Kalman filter. The OD results are compared with conventional range and range-rate measurements and we find that, with three baselines or more, the TDOA and FDOA provides the lowest uncertainty OD solutions except for the case where the chief is in a GEO orbit. When only one baseline is used, the TDOA and FDOA measurements are favorable with lower orbits and a longer observation spans.
Date of Conference: September 19-22, 2017
Track: Astrodynamics