On the effect of laser altimeter crossover observables on orbit determination with the JUICE mission as case study

Abstract

This thesis' work aims to evaluate the potential added benefit to spacecraft orbit determination procedures upon using non-conventional measurements for orbit reconstruction. As a spacecraft orbits a celestial body, its ground tracks will naturally cross previous ground tracks at many points. These locations, known as crossover points, yield valuable information about the orbited body and the spacecraft trajectory using the spacecraft altitude measured during both passages at each crossover location. To evaluate the impact of altimetry crossover measurements on orbit determination, the mission scenario of the planetary mission Jupiter Icy moons Explorer (JUICE) by the European Space Agency (ESA) is used as case study. As the mission's measurements will only be available several years from now, the resulting analysis is done with synthetic measurements obtained through numerical simulations. Herein, the necessary mathematical expressions for the inclusion of crossover measurements into orbit determination algorithms are presented, verified and evaluated. In doing so, it is shown that a first-order approximation of these expressions, as used in previous efforts, is insufficient and a more detailed expression is developed. Furthermore, the used crossover determination algorithm is presented in detail as well as the crossover selection filters in accordance to mission requirements. Finally, the sensitivities and intricacies of crossover measurements are discussed and their added value to orbit determination schemes is shown.