Design And Implementation Of BOC Modulated Signal Generator Based On FPGA

In recent years, the satellite navigation systems of some countries are upgrading, because existing satellite navigation system can't meet the rising needs of military and civilian. As the important method for generating the new generation navigation signals, the BOC modulation will be available for the GPS and Galileo satellite navigation system. Because BOC modulation has partite spectrum characteristic, so that it can ensure to share with existing frequency bands navigation signals. And it has higher code tracking accuracy and better ability of distinguish between multipaths. The foreign research of BOC modulation technology has been in the period of application. As a partner without full ownership of the core technologies and no deep research, China participated in Europe Galileo project. The domestic research of the BOC modulation technology is limit, just focus on receiver algorithm and signal software simulation based on BOC modulation technology. It can not meet the needs of domestic research for the application of new generation navigation signals in the military field.In order to study the generation mechanism of BOC signals deeply, analyse its signal characteristic and carry on the receiving test for new generation navigation signals. The BOC modulation signal generator based on FPGA was studied in this article.Based on mathematical description of BOC modulation and power spectral density and correlation function of BOC signal, it developed the design that used software and hardware cooperation method with the SOPC technology based on FPGA. In the hardware design, the main function modules were integrated into on-chip hardware system as an IP core based on SOPC. In the software design, the BOC modulation signal generator had good charateristics that were real-time, high-speed, continuous signal generation according to the time requirements. The signal generator also can generate the local BOC modulation signal according to the current GPS satellite information in the sky.The implemented design was tested by Agilent E4405B spectrum analyzer and Xilinx ChipScope Pro. The results indicated that the signals generated by BOC modulation signal generator accorded with the requirement in time domain and frequency domain, and the generator has the ability of flexible operations and sets.