Research On GNSS Navigation Signal Baseband Modulation And Control Technology Based On FPGA

The current Global Navigation Satellite System has been widely used in the industry, agriculture, military and daily life, it has not only been used in people's lives for convenience but also produced considerable economic benefits; At the same time, GNSS also plays an important role in the national security and military strategy. GNSS which has been completed or under construction includes the GPS of America, GLONASS of Russia, Galileo of Europe and Beidou of China.For GNSS, the navigation signals have an important role in the system, which is an important part of determining the performance of GNSS service. It must undergo a rigorous design and demonstration whether use a modulated GNSS navigation signals; On this basis, GNSS navigation signals also need the ground semi-physical, physical platform's generation and verifiable system's verification; then the signals need verify through GNSS satellite which in ground and orbit respectively. Thus, the establishment of a set of reconfigurable GNSS navigation signal generation and verification system is necessary, which is the necessary intermediate links which the GNSS navigation signals from design to project achievement.The research content of this paper is an important part of GNSS navigation signals generation and verification system design and engineering achievement, mainly for implementation and research of FPGA-based GNSS navigation baseband signals modulation and control of related technologies. First, the GNSS navigation signals generation and verification system is introduced briefly, and focus on the content of this research related to the main control unit, signal generation and transmission unit and have the detailed description; Secondly, All-Digital Phase-Locked Loop(ADPLL) and GNSS navigation signals which has different modulation are designed and performance analysed, and the result of design is simulated and verified. On the basis, ADPLL and GNSS navigation signals which has different modulation are carried out semi-physical simulation and physical implementation through FPGA technology; Finally, the paper develop for the GNSS satellite navigation signal generator prototype performance test analysis. The result showed that the modulation mode can be changed flexibly and the carrier center frequency can be adjusted in this system. And the system also have a broad frequency range and a high frequency spectral purity. It is verified that the generator can meet the design requirements.