| Summary: | 碩士 === 國防大學中正理工學院 === 軍事工程研究所 === 93 === ABSTRACT
An optimal operation model of determining range and velocity with the use of GPS has been proposed and tested by this research. Based on the principle of deriving range and velocity from the spatial coordinates, the solutions of SPS and DGPS coincided with three mathematical algorithms, namely the epoch interval approach, vertical offset approach, and function fitting approach, have been studied. The range and velocity derived were practically applied to the road distance measurement or shipboard gravity’s Eötvös correction, respectively.
For the trail of road distance measurement, a modified epoch interval approach based on the distance average using every 5-9 or 1-3 epochs of SPS or DGPS solutions, respectively, has been found to be feasible in practice. The average errors of around 15 m and 5 m, or a ration of 0.16% and 0.06% over the total road distance, were estimated by this practical approach using SPS and DGPS solutions, respectively.
For the correction of Eötvös effect in shipboard gravity, the crossover errors (COE) computed can be read as the effectiveness of the use of the velocity derived. It was found from the test data that the average COE is estimated to be up to 28.2 mgal if the Eötvös correction is not applied. However, a much lower of COE of 2.7 mgal can be obtained to meet the requirement of ±3 mgal when the information of the ship velocity and heading are both provided by the epoch interval approach.
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