Near Real-time Tidevariation Inversion Based on the Double Difference Kinematic Positioning

Based on GPS differential phase kinematic positioning program of GAMIT TRACK,ocean tide is calculated in this paper.By comparing the results of combination of different baselines with recorded values of pressure tide gauge,this method is proved feasible and appropriate.By comparing the results of different combinations of ephemeris and baselines,it is concluded that,when the relative-positioning distance is within 150 km,the tide produced with IGS final ephemeris is the most precise one but lags,and the IGS ultra rapid product which can be used in real time GPS tide observing comes second,and the result of the broadcast ephemeris is the worst and only can be applied to real time short baseline GPS tide observing.