Research On Performance Evaluation Technique For Non-Commensurate Sampling Rate And Unambiguous Acquisition Technique For Binary Offset Carrier Signal

As a modern high-tech system, Global Navigation Satellite System (GNSS) has become a symbol of economic and technological power. All the world's major powers are working to develop an independent satellite navigation system. Currently, the existing and under-developed GNSS involve U.S. GPS, Russia's GLONASS, European Union's GALILEO and China's Compass series. Development of high-precision GNSS receivers is the relentless pursuit of the field of satellite navigation, while raising PN (pseudo random) code synchronization accuracy is the core technology to achieve high-precision positioning performance indicators. This dissertation has researched on some key technologies for PN code synchronization in GNSS receiver. The main achievements and contributions are as follows:(1) In the ideal case (ignoring the effect of carrier modulation and demodulation, bandlimiting, thermal noise and interferential), this dissertation researched on the performance evaluation theory for non-commensurate sampling (NCS) technology, which was widely used in GNSS digital receiver. The dissertation proposed a novel quantitative performance evaluation index which can effectively assess the influence of arbitrary sampling rate on time discrimination in GNSS receiver, as well as the corresponding fast calculation algorithm, and as a consequence, obtained the general law of the influence of arbitrary sampling rate on time discrimination. Finally, a preference selection procedure of sampling rate was proposed.(2) To address the ambiguous acquisition problem of binary offset carrier (BOC) signal, this dissertation proposed a novel BOC signal main-peak acquisition algorithm which can balance two important but conflicting performance criterions of side peak suppression performance and noise suppression performance. The basic principle of the proposed algorithm was converting the unambiguous acquisition problem into an equivalent multi-objective optimization problem, and adopting multi-objective particle swarm optimizer (MOPSO) to obtain the Pareto optimal set. The obtained Pareto optimal set provides the best trade-off between several important but conflicting performance criterions. Compared with some similar ones, the proposed unambiguous acquisition algorithm has the following advantages:a) Expanding the vector space of decision variables, which was ensuring the existence of optimal solution with better performance. This dissertation proposed a general tectonic pattern of test criterion which based on proper quadric combination of basic correlators, and then adopted the quadric combination coefficients as the vector of decision variables of the proposed optimization problem. In particular, there exist some Pareto optimal which can completely remove all of the undesired side peaks, and with better noise suppression performance than some similar unambiguous acquisition algorithm of the state-of-the-art. b) Expanding the numbers of optimal objective functions, which provides engineers with maximum design flexibility. This dissertation pointed out that for general BOC (kn, n) signal, when k is large, vice significantly improving the performance of side peak suppression performance will mean a significant deterioration of noise suppression performance, then we should focus on both performances evaluation indexes of side peak suppression performance and noise suppression performance, rather than just one single performance indicator. The obtained Pareto optimal set have the meaning of best trade-off between both conflict performance of side peak suppression and noise suppression in accordance with design requirement, while some similar unambiguous acquisition algorithm of the state-of-the-art can only obtain a single solution to unambiguous acquisition problem, which are difficult to provide the required design flexibility.