Study of Differential Global Positioning

• Main Author: 謝建志
• Other Authors: 高維文
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/10527781295289623569

碩士 === 國立臺灣科技大學 === 機械工程系 === 88 === Global Positioning System (GPS) is an open system with the characteristics of real-time and 3-Dimentional highly precise positioning. Therefore, the researches and applications of GPS have been booming these years. The most critical issue is accuracy , into which most efforts have been taken. By using the pseudorange correction calculated in the reference station, remote receive positioning accuracy can be improved with DGPS method. However, GPS position errors come from different sources with different characteristics. Conventional DGPS method do not take the error characteristics into consideration and produce limited accuracy as a result. In this thesis we proposed different correction methods for errors with different characteristics such as satellite/receive dependency and time variance . For errors result from inaccurate reference receiver position, a self-calibrate method based on pseudo range correction observations is proposed. For slow time-varying satellite dependent errors result from in-accurate atmosphere models or satellite clock error models, an error identification method based on stationary remote receiver assumption is also proposed. By using these methods, we are able to improve the GPS positioning accuracy from about 5 meters for conventional DGPS to less than one meter. This result has greatly extended the application of pseudo range based DGPS positioning method.