電子化全球衛星即時動態定位系統應用於車載移動製圖平台定位表現之研究

A Feasibility Study of Using e-GPS for Mobile Mapping System

移動式車載製圖系統（Mobile Mapping System, MMS）發展至今，已相當成熟。其平台上搭載定位定向系統，並包含多種的感測器。其中所搭載全球衛星定位系統（Global Position System, GPS）具有高精度、快速、方便等多種優點。現今MMS搭載的GPS儀器多為後處理用，此方式雖然能保有高精度，但獲得成果的時間較長。現今台灣內政部國土測繪中心建置了一套電子化全球衛星即時動態定位系統（e-GPS）可以實現即時動態定位，且突破單一參考站RTK的有效範圍限制，帶來更快速、更方便的定位成果。其定位精度之成果與可用性的表現，即成為本研究的目的。本研究嘗試以現行常用的動態後處理，與即時處理進行比較。發現即時處理在產生虛擬參考站時，採用較為嚴格的標準，因此得到的結果相當可靠，但也因衛星的觀測資料篩選較為嚴格，會有覆蓋率降低的情形發生。 Mobile Mapping System (MMS) has been developed quite maturely. MMS is equipped with positioning and orientation systems, including a variety of sensors. One of the sensors is Global Position System (GPS). It has many advantages, such as high precision, fast and convenient positioning. Most of GPS data processing for MMS is post-processing. Post-processing can maintain high accuracy, but it cannot position in real-time. National Land Surveying and Mapping Center has constructed a network real-time kinematic (RTK) system named e-GPS. The e-GPS brings faster and more convenient positioning results. This research aims at using e-GPS for MMS, but the feasibility of e-GPS for MMS is still unclear, so we attempt to compare post-processing and real-time processing. Because environment condition will significantly affect the position accuracy of GPS, we tested MMS in three different types of environment conditions. The results show that real-time processing uses more strict standards for producing virtual reference station (VRS) observations. The results of real-time processing are quite reliable, but real-time processing deletes satellite observations more than post-processing, so real-time processing sometimes leads to reduced number of positioning results.

Mobile Mapping System (MMS) has been developed quite maturely. MMS is equipped with positioning and orientation systems, including a variety of sensors. One of the sensors is Global Position System (GPS). It has many advantages, such as high precision, fast and convenient positioning. Most of GPS data processing for MMS is post-processing. Post-processing can maintain high accuracy, but it cannot position in real-time. National Land Surveying and Mapping Center has constructed a network real-time kinematic (RTK) system named e-GPS. The e-GPS brings faster and more convenient positioning results. This research aims at using e-GPS for MMS, but the feasibility of e-GPS for MMS is still unclear, so we attempt to compare post-processing and real-time processing. Because environment condition will significantly affect the position accuracy of GPS, we tested MMS in three different types of environment conditions. The results show that real-time processing uses more strict standards for producing virtual reference station (VRS) observations. The results of real-time processing are quite reliable, but real-time processing deletes satellite observations more than post-processing, so real-time processing sometimes leads to reduced number of positioning results.