Research Of GNSS Navigation Signals Generation Technology Based On FPGA

Global Navigation Satellite System (GNSS) has become one of the mostchallenging and promising issues in modern information technology. Nowadays, manycountries and regions are currently developing their own navigation satellite systems.There are four existing Global Navigation Satellite System (GNSS) at present, namely,GPS of America, Galileo of Europe, GLONASS of Russia and Compass of China.Frequency band division and the signal modulation are different for each navigationsystems, and the signals play an important role in positioning of navigation satellitesystem. So, it is necessary to make a research of the new GNSS signals theory andmodulation technology.The main research subject of this paper is Galileo system’s navigation signals. Themost prominent characteristic of Galileo signals is using the offset-carrier modulationtechnology. This modulation signals have higher frequency band efficiency than BPSKmodulation signal, and the signals have the advantages of acquisition, tracking andanti-jamming. There are main three modulation technology of BOC, MBOC andAltBOC in Galileo system. This paper analyzes the time domain and frequency domainfeatures of the three modulation technology, as well as their advantages in practicalapplications. On the basis of theoretical analysis, the hardware design programs aboutMBOC signal and AltBOC signal modulated are proposed based on FPGA, and theessential modules such as spread spectrum modulation module, sub-carrier modulationmodule and carrier modulation module are programmed and implemented. Thesimulation graphics show the feasibility of the methods.