Research And Implementation Of Gnss Satellite Simulation Signal Generation Technology

In recent years, satellite communication technology has developed rapidly and major countries have developed their own satellite navigation system, so the satellite signal receiver and simulator has also been more and more researchers’ attention. In the process of receiver research, testing, production, maintenance and repair, we need a satellite signal simulation equipment to produce satellite simulation signal with certain scenario, so that we can test the receiver’s performance of acquisition, tracking and other aspects. After the receiver locates position, we also need a equipment to verify the correctness and accuracy of positioning results. Therefore, satellite simulation signal source is the basis of the research and development of receiver equipment, with huge application value and market foreground.This paper aims to research and develop simulation testing system with good performance, low cost and easy to carry. Around the GNSS satellite simulation signal generation technology, this paper studies the basic components of GNSS navigation system, the characteristics of satellite signal and principle for positioning and speed measuring, and as a case study of beidou B1frequency point, the three layer structure content of navigation message, ranging code and carrier in satellite signal is introduced in detail.On the basis of the above technical background, the paper gives systematical design of the whole satellite signal simulation architecture, including data simulation subsystem, intermediate frequency signal generation subsystem, radio frequency signal generation subsystem and control and assessment subsystem. What’s more, the paper makes detailed introduction of key technology used in the system, such as data alignment, carrier\code NCO, multimode reuse, three choose two output and time synchronization. According to the design scheme, the implementation of the whole system is divided into two aspects of hardware and software, with the upper software+DSP+FPGA architecture and the usage of appropriate chips, the project implementation of the GNSS satellite simultion signal generation system is completed.Finally, this paper carries out necessary tests to the source file of data simulation, signal spectrum, signal quality and system performance, the test results are analyzed.