GPS/GSM整合應用於農用車輛行走軌跡遠端監視系統之初步研究

Abstract

摘要 本研究將GPS精準的定位能力與GSM無遠弗界的傳輸能力，藉由RS-232介面結合，並自行以VB 6.0撰寫軟體，將在遠端行進之車輛路線即時地在本地端的顯示出來，並分別與實際路線及GPS接收器紀錄的航跡比較，為系統未來在農用車輛應用提出初步可行性的探討。 軟體方面考量各地區的泛用性，可讀取不同的電子地圖檔並可自行設定描繪軌跡時使用的不同參考點。並使用人機介面與加入防呆措施，使操作更為方便且不易出錯。 測試範圍為台灣大學周遭與校園內，先以經濟部提供之座標資料為參考點，在GPS未開啟差分修正時，本系統即有不錯的表現；而在差分修正開啟後，因參考點的誤差而須另外訂定一組參考點，惟描繪之軌跡與實際路線便極為雷同。 實驗結果顯示：此系統可即時在本地端觀測到在遠端行進的軌跡，並且在台大校園內大部分地區皆具可信度，因農業上的使用也因多為空曠區域且GPS收訊良好，本系統應極具潛力。若能有效地解決GPS定位在都市的誤差，本系統的應用將更為廣泛。

Abstract In this study, the track matching the actual path of a vehicle by means of GPS (Global Position System) / GSM (Global System for Mobile Communication) technology, can be shown in a remote terminal by a VB(Visual Basic) program. We also compared the tracks drawn in a remote terminal to the tracks recorded in the GPS receiver. These results will provide us with a preliminary assessment towards the application of this system inside agricultural vehicles. The software developed in this study has a function that loads different e-maps so that the software can be used in different places. For ease of use, it has a human-computer interface and a idiot-proof design to prevent any mistakes when using the software. This system was tested in NTU (National Taiwan University) campus and the surrounding area. The Ministry of Economic Affairs, ROC, offered the coordinates of two reference positions of the map. When the DGPS function of the GPS receiver was not enabled, the performance of the system was average. However, when the DGPS function was enabled, the track obtained was not of a satisfactory level, as originally anticipated. Therefore another set of reference points positioned by the GPS receiver must be chosen to improve the reliability of the system’s performance. Experiments showed that this system was usable in and around NTU. There is great potential for this system’s application within the agricultural industry. The amount of wide-open space normally found in an agricultural field causes the errors of GPS to be reduced. If some methods are devised to improve the accuracy of GPS in cities, the system could be suitable for all kinds of purposes.