Navigation Augmentation based on LEO Communication Satellite Constellations

The main objective of this work is to investigation the feasibility and performances of LEO communication satellite constellations as potential navigation augmentation platforms. The further examination of the existing and upcoming LEO communication satellites constellations has been conducted, such as Iridium, Globalstar, Teledesic, One Web, Boeing, SpaceX, Samsung, etc. The comprehensive performances of LEOs for navigation augmentation are evaluated and analyzed in terms of constellation characteristics, footprint, coverage, signal strength, dilution of precision (DOP, including GDOP, PDOP, VDOP, HDOP), number of in-view satellites, with comparation to these of the current global positioning system (GPS), Galileo and Beidou system. The results showed that LEOs present superior performances compared with GNSS systems, and demonstrate promises as navigation augmentation platform for challenging environments. Moreover, the real-time signal-aided navigation method are explored, from user geometry and signal ranging errors to position errors. Then, we proposed a navigation system based on signal of opportunity from LEOs platform. The proposed system relay on a terrestrial benchmark network, consisting of several monitoring stations with time synchronization, to acquire the downlink communication signal from LEOs platforms and then estimates the time difference of arrival (TDOA) between stations with correlation-based blind detection algorithm. The TDOA estimations and geographical position information are utilized to develop the time-delay-based spatio-temporal distribution model, which the user can settle its own position by matching the model with its estimated TDOA values. The proposed navigation system can operate standalone and facilitates the integration of communication and navigation system.