Research And Design Of GPS Constellation Simulator Based On FPGA

Global Position Systen(GPS) can provide us location,speed and time imformation with high precision. Nowadays, it has been widely used as a major means of navigation in many fields, such as aviation, spaceflight, martime, land and so on. With the development of satellite positioning technology, the space positioning system will be diversified inevitably. In this paper, combined with computer technology and taken GPS positioning system as an example, GPS constellation Simulator is studied.The history, the current situation and the development direction of satellite navigation system are summarized in this paper. And then the research and development state of the GPS simulator are presented. The paper gives us a detailed account of the transmission theory and GPS position principle. And a kind of theory module and design principlr is put forward on basis of these theories, which introduces the design notion and compositive module of the GPS satellite constellation simulator. At the same time, the design principle of each module is introduced too.based on the theory research and analysis, the method of implementing the simulator is proposed. The hardware language verilog is used to simulate the satellite signal, while FPGA is used as a platform. The design and implementation of baseband module are also given in detail, which include the C/A code generated modules, navigation message synthetic module, code conversion modules.And issued by the RF modules at last,which compelete the simulation of GPS signal.At the same time, the signal test is given. Oscilloscope, spectrum analyzer and MATLAB simulation procedures are used to validate the test. The result shows that the design meets the requirements and achieves the desired objectives...