在現今社會中衛星導航已經非常普遍的使用在汽車,飛機或是航海方面的定位上,目前在太空中運行的衛星導航系統主要為美國的GPS衛星系統和俄國GLONASS衛星系統,其中又以美國的GPS衛星系統為我們熟知和常用的衛星導航系統,除了GPS和GLONASS衛星系統外,歐盟也自行研發所屬的全球衛星導航系統,稱之為Galileo衛星系統,預計在2008年底系統架設完畢。 Galileo衛星系統有以下幾點特色,主要以民間用途為主要考量,與美、俄導航定位系統原以軍事用途不同,而且可以提供更加精準的定位誤差,並且和現有的GPS衛星系統與GLONASS衛星系統相容配合。 本論文中提出一個適用於同時接收GPS/Galileo衛星訊號的類比前端接收機架構,針對接收機的複數濾波器設計與分析、頻率合成器的非理想效應對後端數位部分的影響,和AGC演算法的設計進行研究與討論。
GNSS (Global Navigation Satellites System) is the general meaning of the satellites-based navigation system. The available two satellite systems include GPS (Global Positioning System) in the United States and GLONASS (Global Navigation) in the Russia right now; and other system, Galileo which is developed by EU (European Commission) and ESA (European Space Agency) will be set up well in 2008. The Galileo satellite system has some following characteristics. It is different from United States and Russia navigation satellite system which aims military purpose object originally. It is mainly for civilian use worldwide. Galileo can provide a highly accurate, guarantee global positioning service under civilian control. It will be inter-operable with GPS and GLONASS, the two other global satellite navigation systems. In this thesis, an analog front end receiver architecture is presented to receive GPS and Galileo satellite signals simultaneously. Furthermore, the design and analysis of the complex filter, the non-ideal effects of the frequency synthesizer and the algorithm of the AGC (Automatic Gain Control) are also discussed.