對GPS全球定位系統的使用者而言，接收機的定位精確度是很重要的，特別是對使 用C/A 碼的單一接收機。在本論文中提出一改進的"GPS靜態定位條正演算法"，利用機率統 計的方式來改善全球定系統的定位精確度。 當S/A效應開啟時，C/A碼的接收機最大定位誤差約為100m，如想要提昇定位的精確度 可能要選擇DGPS的方式或使用可接收P碼的接收器。而目前C/A碼的接收機價格便宜且使 用普遍，因此本文嘗試"以時換取精確度"的方式使用C/A碼的接收機接收多筆的GPS定位資 料，再透過"GPS靜態定位修正演算法"篩檢出較為精確的定位資料作分析，並預估修正後誤 差可能的大小，以達到改善精確度的目的。 經帢驗證實以此方法做GPS靜態定位修正是可行的。當GPS定位資料達200筆時，由 演算法所得預估點的精確度約為25m以內，而當測量數據越多時預估點的精確度也越高。

　　　　　To users of the Global Positioning System (GPS), it is the positioning specificity of receiver, especially the C/A code mono-receiver, that is significantly dominant. In this paper, we would like to provide some kind of algorithm gotten by the probability and statistics to improve the specificity of the GPS. As the Selective Availability (S/A) effect turns on, the maximal positioning error of C/A code receiver is about 100 meters. If we want to improve the positioning specificity, we might have to adopt the DGPS or to use the P code receiver. In this paper, I try to get GPS positioning data, in exchange time for specificity, then select more specific data for analysis, by means of the static positioning modification algorithm, and predict the variation of altered data to attain to specificity promotion. Experiments have proved that this method, the static positioning modified GPS C/A code receiver, is practicable. The specificity of positioning by algorithm is within 25meters as data exceeding in 200. The more data you adopt, the more specificity it achieves.