Research On IF Signal Acquisition System And Data Processing Of BDS/GPS

In recent years,with the increasing application of global satellite positioning systems,GNSS convergence has become a mainstream trend.With the "Beidou ?" navigation system officially providing basic navigation services to the whole world,the goal of networking China's BDS has also taken a substantial step and entered the global era.The BDS/GPS intermediate frequency signal acquisition system designed by this subject based on the background of the development of navigation receivers,it provides a good solution to solve the multi-constellation compatible and interoperable satellite signal acquisition problems,has also played a positive role in the development of the navigation industry:Firstly the hardware and software designs and implementation of the satellite RF signal acquisition system in this thesis are carried out,and converts the received RF signal into IF signal,which provides data for the subsequent acquisition algorithms.According to the functional and technical requirements of the receiving system,firstly designed the hardware structure,then designs each functional modules of the hardware system in detail.The RF front-end was built by using MAX2769 chip,the FPGA(EP4CE15F)was used as the control chip of the system,and using CYUSB3014 as the USB3.0 communication control unit.The data collected by the RF circuit is transmitted to the host computer,to realize high-speed data transmission between the RF front-end and PC;The system software module includes the transmission and control data program of FPGA written by Quartus ?,the USB firmware program developed on Eclipse,and the upper computer program written in VC++,which can realize the reception,transmission and perservation of IF data.In this thesis the functions and indicators of the signal acquisition system are tested by analyzes the results of the captured data.Based on the analysis of satellite acquisition technology,the frequency domain parallel code phase acquisition algorithm based on FFT is adopted.Firstly the algorithm is validated with existing raw data,the simulation results prove the feasibility of the acquisition algorithm,then the IF acquisition system is connected and debugged,and the received data is simulated by the acquisition algorithm,the results are compared with the previous data.The experimental results show that the performance of the IF receiving system meets the design requirements and has better applicability.