Pseudorandom Code-Aided Acquisition and Tracking of Globalstar Satellite Signals for Opportunistic Navigation

Opportunistic navigation using low Earth orbit (LEO) satellites has emerged as a promising alternative and complement to global navigation satellite systems (GNSS). Globalstar is a noteworthy LEO constellation for this application, as it employs a spread-spectrum modulation principle similar to that used in most GNSS systems. A significant challenge in processing Globalstar signals lies in the absence of documented specifications on the spreading code sequences. This paper explores an approach to deriving these codes using the limited available information. It then examines the acquisition and tracking of Globalstar satellite signals for opportunistic navigation. The experimental results validate the successful generation of the pseudorandom codes and the reliability of the signal acquisition and tracking process, highlighting the potential of Globalstar satellites for navigation applications.