Generalized approach to navigation of spacecraft formations using multiple sensors

An investigation was performed to evaluate sensor suitability and performance for formation flying in a variety of spaceborne environments. This was done as a precursor to the development of strategies for novel uses of satellite formations in environments other than Low Earth Orbit. Sensor models were developed to allow for a uniform treatment in processing range measurements. A formation simulation environment was then produced which included representative formation geometries, sensor noises, and navigation filters. The simulated formations included Low-Earth, highly elliptical, and libration point orbits. Equations of motion were modified to account for more accurate propagation of elliptical orbits, and an estimator was designed that allowed for large propagation times without GPS measurements. A high-accuracy transponder measurement was added and evaluated to give improved performance to accuracies of a few meters. A similar study was performed for the libration point orbit without the capability to track GPS signals.