Research To Prerise Qussi-geold At A Little Region Scale

The technology of GPS has infiltrated into different fields of Geomatics,besides, it hasbeen widely used in leveling surveying。It has a lot of advantages as follows: Compared withthe traditional leveling surveying,it is high-efficient as well as practical. On top of this, thetechnology of GPS elevation fitting is becoming better and approaching perfect day byday,the key of which lies in how to switch the geodetic height without any physicalsignificance to the valuable normal height.As a rule, according to different situations, we useheight anomaly as the subject of study and set up proper mathematic model,then use Remove-Restore Technique to fitting with the gravity model.Nowadays, the accuracy of GPS elevationfitting can reach up to centimetre-sized, which can meet the needs in many circumstances.Although the establishment of CQG2000 and quasigeoid in the provincal and municipalagreements brings a lot of convenience to the elevation with the use of GPS, the accuracy ofthose above can't satisfy the requirement of Geomatics .Thus, based on the CQG2000,manyprovincal and municipal organizations has made efforts to study precise Quasi-geoid in theirown district,making great achievements so far.Among these,compared with CQG2000, theaccuracy has improved into a new level,but we still need further study in the potential of localQuasi-geoid. Taking this background into account, in this paper,I will use certain municipalityas the subject of study and analyze the approaches and possibilities of précising local Quasigeoidwhich is based on Quasi-geoid,what's more, I will devise a set of software dealing withsome data in order to the calculation and the analysis of accuracy.In the first place, I introduce the concept of Quasi-geoid and something related as well asthe way to accurate Quasi-geoid. Then, GPS/Leveling, which is one of the ways of accurateQuasi-geoid, comes second. In this part, after using polynomial fitting,MultisurfaceFunction,weighted average method,andLeast Squares Collocation to calculate and analyzetheir range of use respectively, I compare their accuracy and practice . Next, based on theexisting of Quasi-geoid,some research are made on the probability that whether we can use Remove-Restore Technique和GPS/Leveling to accurate local Quasi-geoid or not. In thisresearch, I present the concrete thoughts and steps to calculation and use some real data toanalyze as well as probe into the probablity and advantages of this method. The last but notleast, with Visual Basic being a platform, I design a set of software to comput the date with thelink of matlab。...