Establishment And Simulation Of Vehicle GPS Satellite Mobile Communication Channel

Vehicle-borne GPS communication is an important way to realize vehicle positioning.The quality of communication between vehicles and GPS satellites affects the accuracy of vehicle positioning.In order to achieve more precise positioning and navigation of vehicles through application of GPS satellite and make communication between vehicles and GPS satellite efficiently when used in Internet of Vehicles,fading characteristics of the communication channel between GPS satellite and vehicles in driving state were studied thoroughly and the correct and effective communication channel model between GPS satellites and vehicles together with its deterministic model were established in this thesis.In the vehicle-borne GPS satellite mobile communication system,the vehicle which is the receiving end has the characteristics of high-speed movement,limited driving area to the road,and frequent switching of scatterers around the environment.Considering the difference of fading characteristics of communication channel between GPS satellites and vehicles in diverse environment,the scene of vehicles driving was divide into three parts which were open expressways,suburban roads and complex urban highways respectively.Three classical vehicle GPS satellite communication channel models in three scenes were analyzed.Because the driving area of vehicles is limited to the road and the scatterer environment around most scenes is inhomogeneous,a extended Rice channel model was proposed according to analysis of fading characteristics of the communication channel in this thesis.Besides extended classical channel models in three scenes were proposed based on the extended Rice channel model.Considering real condition of transmission,these models proposed above assumed that the scattering environment of receiving end is nonuniform and the Doppler spread power density spectrum is asymmetric caused by multipath scattering.Therefore the actual scattering environment could be simulated by configuring the two-terminal truncation frequency.Furthermore,first-order statistics and second-order statistics of these three extended models were induced in detail.These extended models were fitted well with the measured data which verified the feasibility and accuracy of these extended models.On the top of that,deterministic models of three extended satellite channel models were implemented based on the colored Gaussian random process.Method of Exact Doppler Spread was also introduced to calculate Doppler parameters of deterministic models.Simulation results of the deterministic models were fitted well with its theoretical values,which verified the validity.Finally,to simulate the switching of channel of vehicles running in different environment,a three-state Markov model was introduced and analyzed in this thesis.By statistic of the change of terrain scene in the selected area,the Markov transfer matrix of scene change can be calculated,which contributes to predicting the fading characteristic change of vehicle GPS satellite communication channel.The established vehicle GPS satellite mobile communication channel model in this thesis achieved the purpose of describing specific scenarios using specific models,which could provide a theoretical reference for accurately describing the transmission characteristics of vehicular GPS satellite channels.