Data Base Establishment And Study On The Estimating Algorithm Of The System For Testing Gps User Equipment

GPS is able to provide the service of hight precision positioning and timing. It is well known that the function of the satellites navigation system will not take effect without user equipments. Therefore the system for testing GPS user equipment is constructed in order to estimate all capability criterions of GPS user equipment. This paper has studied the database establishment and the estimating algorithm of the system for testing GPS user equipment specially.First of all, this paper analyzed the components which make up of the system for testing GPS user equipment, primary functions of every single part, and the testing items. Next, basic knowledge of GPS satellites navigation system was systematically summarized. Constellation configuration, time and coordinate system, signal configuration, and navigation message of GPS satellites navigation system and etc. were introduced. Meanwhile, configuration, category, working principle and data interface of GPS user equipment were analyzed. Finally, on the basis of all the above contents, the database establishment and the estimating algorithm of the system for testing GPS user equipment were studied. Also the software of database management and evaluation of the testing system was developed.Contributions of this paper are as followed.Firstly, some knowledge of GPS satellites navigation system, GPS user equipment, and the system for testing GPS user equipment were systematically introduced.Secondly, data for storing, data types, and relationships of data of the testing system were educed on the basis of having analyzed GPS user equipment working principle and its data interface , testing system, as well as testing items. According to the above , E-R models of database were built. By analyzing E-R models, database tables were designed, and the database index and relationships of tables which make the data search convenient and keep the data whole were built.Thirdly, aiming at every testing item, the estimating algorithm of the user equipment capability test was studied in depth. The process of evaluation of the capability test were constituted in reason. Evaluation methods and the process of evaluation of sensitivity test, ranging accuracy test, positioning precision test, and test for velocity measurement precision were analyzed and studied specially. Three different evaluation methods of ranging accuracy test were analyzed and compared, and the advantages and dis advantages of the methods were summed up.Fourthly, the software of database management and evaluation of the testing system were developed. The database management and the estimating algorithm of the user equipment capability test were integrated effectively into the software. By humanizing the design of the interface of the software, it made communication between man and computers possible and also brought convenience to the use of the software. Report forms of evaluating results were designed in reason. The reliability and stability of the software, the integrality of the storing data, and the correctness of the estimating algorithm were proved by having used the software in the process of testing user equipments of about 20 manufacturers.