Development And Applications Of GNSS Data Quality Assessment Software

With the application of BeiDou satellite navigation system,BDS/Global Navigation Satellite System receiver based on carrier phase observation is widely used in related fields.The observation data quality analysis of GNSS receiver is essential part in the implementation of high-precision measurement.It can provide an import method of observation data quality checking for the surveying operation and also offer some priori information for data post-processing.Now there are lots of data quality analysis softwares.Nonetheless,the function of software is incomplete and it is difficult to benefit the majority of GNSS users due to the strong confidentiality of processes on product development and technology.In the light of loading conventently and application freely by own data quality analysis algorithm it is very necessary that kinds of own GNSS data quality assessment software are developed.Therefore,a set of GNSS data quality assessment software is developed based on C++ Builder and data quality assessment system,which could be in the service of many practical applications.The main research contents and conclusions in this paper are as follows:1)In view of the present state that evaluation index and computing method of data quality analysis software is inconsistent at home and abroad,the index system of GNSS receiver observation data quality assessment is established by combining the assessment indexs in many business and research software,which includes data integrity rate,observations per slip,etc.The definition of data quality assessment indications is determined and the criterion of assessment method about each index is produced.2)The software system is designed into three parts,i.e,data layer,business logic layer and presentation layer for user interaction,according to mainstream support for current graphical user interface application.The scheme follows the typic design of three parts,which possesses compactness,portability and expandability.3)GNSS data quality assessment software is developed.This software possesses perfectly fuction,friendly interface,high ability of visualization and strongly expansibility.It especially develops visualizational modules of data quality assessment and analysis,data format conversion and editing,data reception and download,etc.In the interaction of data layer and logic layer,the software can deal with multi-system and multi-frequency any version of RINEX observation data file at the same time to complete the task of quality assessment analysis for all indexs.Detailed results files of all indexs are exported based on designed analysis result format.In the aspect of presentation layer,visualization and interactive function for single index,single frequency,single channel,single satellite,etc can be realized.4)Many kinds of application are carried out based on GNSS data quality assessment software.First,data quality of all stations of global is analyzed by using software and these results are applied to site selection strategy in global ionospheric delay modeling.It is proved that computational efficiency and accuracy of global ionospheric TEC grid products are improved.Then,the observation data quality that are receivered from different receivers are analyzed by applying self made program during the test work for GNSS receiver,thus refecting performance differences between receivers;Finally,carrier phase observation in source file are corrected based on carrier-to-noise ratio and elevation angle that are exported by self made program so the accuracy of precise point positioning is improved.