GPS(Global Positioning System)為一定位系統，使用者利用一接收器接收天上衛星之訊號並對自己的位置進行解算。然而衛星訊號經過漫長的旅途之後傳達至地面的使用者已有許多的干擾。例如電離層效應、多路徑以及軌道誤差等。訊號的失真對地面的使用者而言則會影響其定位之精度。本論文目標為建立一虛擬衛星，利用其能發射與天上衛星相仿之訊號，不但能加強GPS定位精度，更在製作完成雙頻虛擬衛星發射器後，提昇RTK之測量，而達成更精準之定位。

Pueuodolite(pseudo-satellite)can transmit GPS-like signal to enhence the accuracy and integrity in GPS positioning. The thesis describes the design of implementation, and fest of a dual frequency pseudolite. Through the implementation of dual frequency pseudolite, RTK positioning can be greatly enhanced.

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