Research On Enhancement Network Optimization And Precise Timing Synchronization For Air-borne Pseudo-satellites Of Beidou

Although Global Navigation Satellite System is able to provide navigation service of highprecision, all-weather and global coverage, imperfect neutrality, poor reliability in complex terrainand weak adaptability and coverage are its shortcomings. The second generation of BeiDouNavigation System is to perfectly, which is to navigate around the global in2020.Pseudolitetechnology is one of the effective ways of the problems. Based on this point, the thesis studied thelarge area pseudolite strengthen system of second generation. The thesis investigated the networkingand dynamic timing technology of pseudolite system deeply and put forward the method ofcomposing semi-analytical approach and genetic algorithm. This thesis pointed out some methodssuch as the net average, satellite common-view selection, position compensation, track iteration whicheffectively deals with time error of the system.Firstly, in order to solve the problem of wide area pseudolite network, the solution that combinedthe semi-analytical and genetic algorithm was proposed. Numbers of investigations was done toanalyze the advantage and weakness of semi-analytical methods and genetic algorithm, respectively,put forward the method of composing semi-analytical approach and genetic algorithm. Moreover, theperformances of various indicators which have been defined to calculate the optimized configurationfor the air-borne pseudo-satellite network, were verified through Analytical Hierar-chy Process.Ultimately, the preferably one was chosen.Secondly, the method of satellite common-view selection and net average were used to solve theproblem of the time synchronization for dynamic carrier, which was considered hardly to complete bythe method of common-view time service traditional. First, The thesis analyzed the principle andcharacteristics of common-view time service and proposed the method of transmission common-viewtime service.Then, the errors of common-view time service was analyzed and put forward the methodof satellite common-view selection in order to reduced the effect of troposphere delay.following this,the distribution of position error of the SIN/BD integrated navigation system, then raised the methodof net average to improve the precision of common-view time service. In the end, using Kalman filtersimulated and verified the accuracy of the system.Finally, basing on the traditional double sides two-way time synchronization, this article usedStrpdown Inertial Navigation System which was high-precision in short time and dynamic positioncompensation to solve the problem of dynamic carrier time synchronization. First, the principle of double sides two-way time synchronization was analyzed and researched, and a strategy that usedposition compensation to eliminate the movement error was presented. In order to getting the timedifferent of pseudo satellite which moved in a specific orbit, tactics was proposed.By analyzing onthe principle in calculation and the accuracy in short time of SINS,Then, double sides two-way timesynchronization was simulated by the strategy which was proposed under the condition of GEO andIGSO. Finally, the results show that the strategy which was proposed could improve the accuracy ofdynamic double sides two-way time synchronization.