Determination Of Ocean Tide Loading Based On Precise Point Positioning

The water in the ocean tides moves back and forth and these mass redistributions cause periodic loading of the ocean bottom.Since the Earth is not completely rigid,it deforms under this load and this is called Ocean Tide Loading.The vertical displacement of OTL could reach up to serval cm at some special coast regions.In my paper,on the base of further research of PPP,it is applied to determine OTLD.The main works and conclusions in the thesis are as follows:?1?The function model,errors processing method and parameter estimation method of PPP were elaborated in detail.Four common PPP models internationally were analyzed respectively.The main error sources which affect the accuracy of PPP and the methods of calculating or eliminating these errors were studied.Furthermore,principle of Least Squares Adjustment and Kaman filters was described in detail.On the basis,data provided by IGS was carried on examination validation.?2?Influence of OTL on PPP.Using the global ocean tide model,the OTLD were calculated and analyzed for 10 IGS stations in China and the surrounding areas.According to the comparisons,the vertical displacement of OTL at stations is larger than the horizontal displacement and the OTLD in coast stations is larger than OTLD at continental stations.PPP sub-daily and day solutions are investigated when OTLD are modeled and then not modeled.For PPP daily solution,the OTL correction have no effect on the station coordinate,but for PPP sub-daily solutions,the OTL correction can improve 2mm accuracy on the coastal stations.?3?Determination of OTLD based on PPP.Using the Benese5.2 PPP,coordinates were calculated and analyzed for 8 IGS stations on AZORES islands and coast area of Portuguese.The periodic characteristics of constituents?M₂,S₂,N₂,K₂,K₁,O₁,P₁,Q₁?were extracted by the least square spectrum analysis.After the harmonic and least square spectrum analysis,OTLD of constituents were obtained.The result show other constituents are good agreement with global ocean tide models except for K₁,K₂ and P₁ constituent.With the exception of Ki constituent,the accuracy of other constituents between AZORES islands and coast area of Portuguese is the same.