Orbit Determination Methods for Deep Space Drag-Free Controlled Laser Interferometry Missions

Abstract

The objective of this thesis is to determine if different measurement combinations will improve absolute and relative orbit determination (OD) accuracy for the Laser Interferometer Space Antenna (LISA) mission. LISA, a triangular three-satellite heliocentric constellation, measures the relative length changes between spacecraft. The unique contribution of this work is the incorporation of inter-spacecraft range and range rate observations into the OD process, in addition to Deep Space Network (DSN) range and range rate, and Very Long Baseline Interferometry (VLBI) angle tracking data. MATLAB was used for orbit propagation, simulating measurements, and executing the weighted batch least squares algorithm to obtain the best state estimate. Covariance and Monte Carlo analyses were performed to compare the four test cases. The results concluded that cases with inter-spacecraft data had the least absolute and relative OD errors, VLBI eventually becomes ineffectual, and DSN needs at least 20 days of tracking to become observable.