| Summary: | 碩士 === 國立交通大學 === 土木工程學系 === 100 === In this research, a GPS multi-antenna system has been built in the campaigns of collecting shipborne gravity with 1-Hz data rate. The positioning package TRACK is used for kinematic relative positioning (KRP). The assessment of baseline length suggests that the accuracy of KRP from TRACK reaches 1cm in a static condition and 2 cm on a ship. A computer program has been built to compute ship attitudes from kinematic baselines by the direct computation formulas (DCF). The estimated attitudes are used to correct for the antenna height to the sea surface due to attitude effect. The comparison between GPS and GPS/INS-derived attitudes suggest that GPS attitude system and DCF function properly. With the attitude effect accounted, the RMS crossover differences of the corrected SSHs are improved by 0.5 cm, or 3.31% relatively, compared to the case of raw SSHs. With the ocean tide corrected, the difference between corrected SSHs and DTU10 modeled values are reduced by 0.7 cm in standard deviation along straight survey lines, and by 1.4 cm along non-straight lines, corresponding to relative improvements of 3.45% and 4.07%, respectively.
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