| With the emergence of technologies such as the Internet of Things and the Internet of Vehicles,large number of applications based on satellite navigation will emerge.In the railway industry,many new methods are provided for location-based services.Because the new application demands more and more stringent requirements for the navigation system,study on the electromagnetic sensitivity performance of navigation and positioning receivers under typical interference is helpful to analyze the electromagnetic compatibility rectification measures of navigation and positioning receivers,so as to provide ideas for formulating the unified electromagnetic compatibility standards,and improve the safety and reliability of the system.Based on the analysis of the principle of satellite navigation pseudo-code ranging,this thesis studies the influence of typical radio frequency interference on the pseudo-range observation process of the navigation receiver from both theoretical and simulation aspects,and analyzes the positioning deviation caused by single-frequency interference through Monte Carlo simulation.Then,according to the receiver principle,software receiver model and some experiments are completed to verify the theoretical research,which provides a feasible technical solution for the analysis of the susceptibility of the navigation receiver to space electromagnetic interference.The main research works of this thesis are as follows:First,the basic principles of GNSS are analyzed.This thesis mainly focuses on analyzing the principle of pseudo-range measurement in the system,and introduces the error sources of GNSS.And the topic of signal transmission time accuracy for pseudo-range measurement is studied.Secondly,the theoretical connection between interference and pseudo-code phase measurement error is established.Through studying the mathematical relationship between radio frequency interference and the carrier-to-noise ratio of the GPS receiver correlator,and the relationship between the carrier-to-noise ratio of the GPS receiver correlator and the phase error of the pseudo-code,the model between radio frequency interference and pseudo-code observation error is established.In addition,the connection between interference and positioning deviation is also established.According to the GPS pseudo-range single-point positioning principle,a positioning solution model is established through MATLAB.Based on the relationship between three statistically stable interferences and pseudo-code observation errors,Monte Carlo simulation is used to study the positioning deviations caused by different interferences.Finally,the software receiver is modeled according to the receiver principle,and the theoretical model of interference and pseudo-code phase observation error established in this thesis is experimentally verified.It shows that the theoretical model of interference and pseudo-code phase observation error established in this thesis is correct.Theoretical and simulation results show that the positioning deviation caused by narrowband interference,matched spectrum interference and broadband interference is close to 12.6m,when the interference signal ratio is less than 20 d B.With the increase of interference power,the position deviation under narrowband interference will increase faster.It shows that narrowband interference has a greater impact among the three types of interference,and the prediction model of positioning deviation under different interference signal power ratios of narrowband interference is fitted by section.In addition,the influence of pulse interference is classified and discussed in the theoretical analysis according to the relationship between its spectral line and C/A code spectral line.The simulation results show that the higher the pulse repetition frequency,the greater the pseudo-code phases error,and the faster the pseudo-code phases error increases with the increase of the interference signal ratio. |
PDF Full Text Request