Development of Software Library for Open Source GNSS Receiver with Focus on Physical Layer Signal Processing

Abstract: In order to directly interface with signal broadcast by global navigation satellite systems (GNSS) – such as GPS or Galileo – for the purpose of calculating location, a potential user is required to extract great amount of information from interface control documents (ICD) as well as build custom software tools to process this information. This is time consuming and inefficient. Instead it would be great if such tools and information was readily available in one single project. This thesis addresses this issue by designing a universal data structure which is able to accommodate all necessary information to interface with any GNSS. Universal GNSS data structure is designed in such a way so that software tools can be entirely generic across all GNSS, i.e. do not include any functionality specific to only one GNSS. This is done by embedding certain logic parameters inside data structure itself, which determine how software tools behave. The data structure realized in the form of XML file with specific rules and syntax. Data from GPS and Galileo ICDs is scraped and compiled into XML file. A Rust tool-set is created to read XML file and extract information such as pseudo-random noise codes and navigation message structure. Using this information, it is possible to decode a raw bit stream broadcast by GNSS spacecraft, although currently additional tools need to be added to completely automatize this process.