GPS Elevation Fitting Method And Its Engineering Application

The global positioning system (GPS) measurement technology, not only for themodern surveying and mapping technology brings about new technologies, newmethods, new means, brought the technology shocks larger but also to the routinemeasurement method. With the GPS measurement technology is becoming moremature and perfect, the plane measurement of high precision, low accuracy of altitudemeasurement in more and more attention. Therefore, the precision of GPS geodeticheight into normal height fitting of high used in daily life has gradually become a hotresearch area of GPS.This paper briefly introduces the relationship between three kinds of commonlyused height system and mutual conversion, as well as domestic and foreign GPSelevation fitting method, introduces the used method of GPS elevation fitting: contourinterpolation, curve fitting, surface fitting and BP neural network method. Combinedwith three different types of projects: the ground subsidence of Beijing project, theground fissure project and the Beijing karst water resources exploration andevaluation of project,respectively by polynomial fitting and polyhedral functionmethod, scope of application of GPS in the study area measurement data ofmonitoring points existing and leveling data, through different sites using theMATLAB software, programming calculation, the study area was elevation fitting,and the results were evaluated by fitting precision. Finally, by comparing the fittingresults, draws the related conclusion.The thesis is divided into five chapters, as follows:Chapter I: The background and significance of the topic, research status at homeand abroad, the purpose of this study, the main content of research and the structure ofthe thesis are briefly introduced;Chapter II: Introduce three kinds of commonly used system of elevation, and therelationship between the three systems, the principle of GPS height measurement aredescribed, analyzed the source of GPS height measurement error and the way toeliminate or weaken the error;Chapter III: Introduced the used method of GPS height fitting: contourinterpolation, curve fitting, surface fitting and BP neural network method, and theaccuracy of GPS height fitting are briefly described;Chapter IV: Combined with three different types of projects:the groundsubsidence of Beijing city project, the ground fissure project and the Beijing karstwater resources exploration and evaluation of project,for the application of GPSheight fitting, and the application results were compared and analyzed;Chapter V: Conclusion and Prospect of this thesis, the GPS Gao Cheng fitting aresummarized, points out the shortcomings, also on the future prospects of GPS GaoCheng fitting are discussed.