Relative Navigation for Satellite Formation Flying based on Radio Frequency Metrology

To increase mission return, utilizing two or more spacecraft instead of one may sometimes be superior. This is especially true when a large spaceborne instrument needs to be created through larger and configurable baselines, such as telescopes and interferometers. However, coordinating the alignment of the individual components of such a spaceborne instrument on separate spacecraft (involving the estimation and control of baselines) will require a high level of accuracy for relative navigation and control. The increasing demand of such science missions or challenges on complex functions such as rendezvous and docking calls for high accuracy levels of ranging at centimeter or even millimeter levels. The objective of this research is to investigate key technologies of developing a relative navigation system based on radio-frequency (RF) metrology. This RF-based system inherits Global Navigation Satellite System (GNSS) technologies through transmission and reception of locally generated GNSS-like pseudo random noise (PRN) ranging codes and carrier phases via inter-satellite links. This enables operation, e.g., in high Earth orbits where GNSS constellations are poorly visible. The RF-based navigation system is designed to comprise one transmitter, one receiver and several antennas in order to enable coarse-mode inter-satellite distance estimation (meter level) based on pseudorange measurements and fine-mode distance (centimeter level) and line-of-sight (LOS) estimation (sub-degree level) based on carrier phases in addition to pseudorange. A benchmarking system, called the Formation Flying Radio Frequency (FFRF) sensor, has been successfully shown and demonstrated on PRISMA mission. This research improves the performance of FFRF with respect to the technologies 1) to deal with errors and uncertainties, especially multipath; 2) to perform an unaided, fast and reliable carrier phase integer ambiguity resolution (IAR); and 3) to share channels among multiple spacecraft. Mul
Space System Engineering
Aerospace Engineering