Research And Implementation Of Ntrip Differential Data Standardization And Reliable Transmission

In order to improve the precision of navigation,china want to build a BD Ground-based enhanced system.In the process of system design.we separate data standardization alone.It can make the standardization module separation and reduce mutual dependence.According to this,This paper plans to construct data standardization platform.The main task of standardization platform is to receive the bunary data from the 150 ground base station.Then the datas are standardized.Based on the needs of standardization platform,we must research data standardization and data transmission.Last,this paper must realize platform.First of all,the research on data standardization and transmission start from the following three aspects,including the study of data standardization methods,the study of the standardization process,and the study of reliable data transmission.First,the data standardization method are studied from the comparison of RINEX,BINEX,and the various versions of RTCM.It was found that RINEX does not meet the real-time requirements.BINEX meets the real-time requirements of the platform but is difficult to implement.The compression effect and transmission efficiency of the data are not as good as RTCM.Comparing the RTCM of various versions,we finally find that the extended version of the RTCM3.2 standardization method is more standardized and meets the requirements of the Beidou high-precision positioning requirement in China.Therefore,we use the extended RTCM3.2.Second,we study the characteristics of various data and apply RTCM3.2 to practical projects for BD,GPS,and GLONASS datas.The corresponding standardization process algorithms for all types of data are finally obtained.Third,through Ntrip Caster's authentication,observer mode,free configuration,lock mechanism,and backup deployment research,it is determined that Ntrip Caster can enable reliable data transmission.Then,based on the research results,the data standardization platform is designed and implemented.The entire platform is divided into four modules: a data receiving module,a sticky packet parsing module,a standardization module,and a data transmission module.The overall design of the standardization platform is performed through packet and class diagrams.This paper achieve the major modules through the flow chart and Sequence diagram of each module.It focus on the design and implementation of the two major modules including standardization research and data transmission.Finally,the platform is tested in the actual environment.The test steps and results were recorded through the form,and the test results were supplemented with the actual performance graph.Navigation data and original observation data are standardized as RTCM.The standarded data can be identified.The results are correct and can be used effectively.The platform runs about half an hour.In the case of per second data of the same type in each station the standardized data is about 900 KB,and the transmission rate is about 4kbps per station.We can ensure that the platform can be putting into use through the Chinese RTCM3.2 standardization and Ntrip Caster transmission method.