本篇論文的目的，在於利用現有的GPS環境，學習製作GPS接收器的基頻電路與天線，使得我們往後，可將這些設備應用於導航或是大氣的量測及其他運用；GPS的接收器包含了接收天線，RF端電路與基頻端電路，接收天線需全向性與主波束大，以利於接收天空的所有衛星，同時需產生右旋極化去接收衛星所發射的右旋波，我們將先以理論分析、經由模擬得到天線的尺寸，最後實際量測天線的效能；而基頻電路包含了擷取(acquisition)與追蹤(tracking)，擷取(acquisition)是偵測哪顆衛星所發射的訊號，以及其相位偏差，再經由追蹤(tracking)修正訊號的相位，解調出我們所要的星曆資料，我們使用sirf的晶片GRF2e實現基頻電路，將得到星曆資料，並經由ROM內的演算法來定位座標 The GPS receiver consists of three principal components: antenna, RF module, and Digital process. Satellite signals are received via the antenna, which is right-hand circular polarized (RHCP), and should cover a wide spatial angle to receive the maximum number of signals. We use Computer-Aided design software to simulate, and measure by instrument to adjust antenna size. After signal frequency is converted to a desired frequency and digitized by RF module, the digital process use to acquisition and tracking signal. Acquisition means to find the signal of certain satellite. The tracking program is used to find the phase transition of the navigation data. Then the navigation data can obtain to calculate user position. We use a chip sirf GRF2e to materialize Digital process and via the algorithm from ROM to obtain the user position. This thesis is focus on antenna design and the fabrication of digital process for GPS receiver.
