全球定位系統中金氏碼之應用

The Application of Gold Code in GPS

「全球定位系統」(GPS, Global Positioning System)採用「分碼多重進接」(Code Division Multiple Access, CDMA)作為展頻(Spread spectrum)的方式，以在同一個無線電通道的有限頻寬中，納入多個發射器發射的不同訊號。以GPS 而言，要在該通道之內，容納GPS 星系所有衛星各自發射的訊號。「金氏碼」(Gold code)是CDMA 方法中的一種編碼方式，由於其所具有的許多優點，成為GPS 選擇的編碼方法，應用於其C/A、P(Y)、M 碼的編碼。本文目的在簡要介紹「金氏碼」，以為全球導航衛星系統(GNSS, Global Navigation Satellite Systems)使用者之參考。本文定位為教學資料之整理，而非研究成果之展現。

Global Position System (GPS) utilizes Code Division Multiple Access (CDMA) for spread spectrum, in order to let several transmitters can send information simultaneously over a single communication channel. For GPS, that is within a limited specific bandwidth, let all the satellites of this constellation transmit their own signals. Gold code is one of the coding scheme for CDMA. Due to a number of advantages, Gold code was chosen for the coding scheme of C/A, P(Y), M code in GPS. This article introduces the basics of Gold code as reference for the users of GNSS (Global Navigation Satellite Systems). This note is intended to serve as a supplementary learning material, not presenting the result of academic research.