Next Generation Multi-System Multi-Frequency GNSS Receivers
|Kustantaja||Tampere University of Technology|
|Tila||Julkaistu - 1 syyskuuta 2017|
|Nimi||Tampere University of Technology. Publication|
With the availability of multiple satellites systems, the user benefits mostly from the improved visibility of the satellites. The increased availability of satellites naturally increases the computational requirements in the receiver. The main focus of the presented algorithms is on critical factors like provided accuracy versus low cost, low power consumption. In addition, the presented algorithms have been collected into a comprehensive navigation algorithm library where they have additional value for educational purposes.
The presented navigation algorithms focus mainly in the GPS and Galileo systems, with the combination of L1/E1 & L5/E5a frequencies. A novel GPS + Galileo dual frequency receiver was developed by the team over the years. Where applicable, the thesis collects important facts from modern GLONASS and BeiDou systems.
The first part of the thesis introduces all available open service signals from the GNSS systems, revealing how vast the scope of multi-system, multi-frequency receiver design is. The chapter continues with introduction to the basics of GNSS systems, and description of the problems that the receiver designer must overcome. The chapter further continues by describing a basic receiver architecture suitable for multi-system multi-frequency reception. The introductory part also has a short section is dedicated for underlining the importance of testing mechanisms for a novel receiver under development.
The second part of the thesis concentrates on the baseband processing of the GNSS receiver. Topics cover acquisition and tracking, with multi-system multi-frequency implementation Abstract details kept in mind. The chapter also contains sections for issues that must be handled in high sensitivity receivers, e.g. cross-correlation and cycle slip detection. The second part of the thesis is concluded with a description how Assisted-GNSS capability would alter many of the design considerations.
The third part of the thesis describes algorithms related to the data bit decoding issues. All the different satellite systems have their own low-level navigation data structure with additional layers of error detection / correction mechanisms. This part of the thesis provides the algorithms for successful decoding of the data.
The final part of the thesis describes the basic navigation solution algorithms suitable for the mass-market receivers. In this part, the method of combining the measurements from the different satellite systems is discussed. Additionally, all the issues of processing multisystem signals are collected here, and in the end the Position, Velocity, and Time (PVT) solution is obtained.