Study On Main Components Of Tides Based On Global Positioning System

The integration and overlapping between GPS(Global Position System)and other spatial technologies not only extends GPS application area,but also provides a new method and opportunity for other subjects' development.By analyzing the impact of ocean tide loading to the GPS position result,we launch the research of ocean tidal character.This is one of the newly research hot spotsof overlapping and integration between GPS and tidal scienceand has abundant science and practice value.In this paper,we use GAMIT to process four GPS stations along China's coasts.Taking four process strategies to get stations' displacement time series:using the 1 hour and 3 hours time window when static mode and using IGS and IGR ephemeriswhen static simulate kinematic mode.Based on these,applying spectral analysis to derive 8 main tidal character parameters and compare the results with the ocean tide models to analyze.The final results show:(1)Ocean tide loading has an impact of centimeter level in the research area and the description of the tidal character in the same area from different global tide models are not same;(2)From theory and practice,it is feasible to derive tidal character base on GPS technology,and apply the derived character parameters as ocean tide correction can make the GPS position result more correct and stable;(3)Better GPS solving solution and higher sampling rate will benefit the inversion of ocean tidal character,1 hour sampling rate can detect more ocean tides than 3 hours sampling rate and the inversion results are impacted by the GPS residual;(4)Satellite orbit's precision impacts the inversion result of K2,K1 a lot,the difference between IGS ephemeris and IGR ephemeris of K2,K1 from 3-10mm;(5)In the same research area,the results of PPP and difference havea good consistency,but the result of PPP are much more suitable for distinguishing different tide and deriving.