Precise Determination of Hong Kong Geoid Using Heterogeneous Data

[摘要] The precise determination of local geoid is of considerable importance not only for surveying and mapping but also for studying some related problems of geophysics, oceanography and geodynamics, and now especially for applying GPS technique to determine orthometric or normal height in geodesy and surveying engineering. In the paper, based on the remove restore technique, the Hong Kong gravimetric geoid with resolution of one kilometer has been computed using high degree global spherical harmonic geopotential model WDM94, gravity anomalies and digital terrain model which covering the whole territory of Hong Kong and its neighboring region. By comparing with precise GPS/leveling data the standard deviation of the geoid is 7.6 cm, and the relative accuracy about 4ppm for baseline length longer than 50 km. The results illustrate that the systematic bias exists obviously between the two types of geoid heights. Employing four parameter transform model the gravimetric geoid can be improved significantly by precise GPS/leveling data. The results show that the