近年來，全球定位系統(GPS)已被廣泛應用於日常生活中，最常見的應用為車載定位裝置，可被用於目的地規劃與導航、提高行車安全等方面。然而，在不使用校正系統的情形下，全球定位系統仍有10-15公尺的誤差。這些誤差來源來自於衛星星曆誤差、接收器時間誤差、大氣層干擾與多重路徑誤差等。現今所發展的校正系統中，雖可有效校正大部分誤差，提升定位精準度至3-5公尺，但必須架設較為昂貴的設備，如：地面參考站、地面主控站或是地球同步衛星等。在此篇論文中，我們提出了一個不需要架設參考站的車載協同式合作校正方法。並利用真實的GPS封包實驗此校正方法，實驗結果顯示，此方法可利用成本較低的設備有效提升GPS定位精準度。

In recent years, the global positioning system (GPS) has been extensively used in the daily life. The most common application is a vehicular positioning device for planning and navigating the destination and promoting traffic safety.
However, GPS has an error of about 10-15 meters without using calibration. The positioning errors are caused by signal arrival time errors, atmospherics effects, ephemeris errors, multipath errors, and other effects. The present calibration systems can reduce the position errors to 3-5 meters. But the systems have to set up the reference stations, the master stations, or the GEO satellites. In this thesis, we proposed a reference-station-free calibration method to calibrate the GPS position using cooperative vehicles. We experiment our calibration method using the realistic GPS data. The results show that the calibration method can improve the accuracy performance of GPS positioning notably.

[1] B. W. Parkinson and J. J. Spilker, The Global Positioning System: Theory and Appli-
cations, Volume II. Washington, D.C.: AIAA, 1996.
[2] Manolakis D. E., Ecient solution and performance analysis of 3-D position esti-
mation by trilateration, Aerospace and Electronic Systems, IEEE Transactions on ,
1996.
[3] ”Introduction to the Global Positioning System for GIS and TRAVERSE”, Corvallis
Microtechnology, Inc. 413 S.W. Jeerson Avenue Corvallis, U.S. Publication, June,
1996.
[4] G.J. Morgan-Owen and G.T.Johnston, Dierential GPS positioning Electronics &
Communication Engineering Journal , 1995.
[5] Russell J. Keller and Mark E. Nichols, Methods and apparatus for precision agricul-
ture operations utilizing real time kinematic global positioning system systems U.S.
Patent 6199000, Mar 2001.
[6] James E. Robbins, Dierential gps positioning using Virtual Stations U.S. Patent
7711480, May 1995.
[7] http://www.egps.nlsc.gov.tw/index.html
[8] Richard B. Langley, NMEA 0183: A gps receiver interface standard, GPS World ,
1995.
[9] Ormand D., Wide Area Augmentation System (WAAS), Precise Time and Time In-
terval (PTTI) meeting, 1999:155-160.
[10] http://igscb.jpl.nasa.gov/components/prods cb.html