由於現今發送GNSS(全球導航衛星系統)訊號的衛星數目不斷增加，所以擷取流程所需要花費的時間也就相對提升。這篇論文提供一個新的擷取方法能夠同時擷取兩個或兩個以上的GPS(全球定位系統)L1的訊號，而其所花費的時間相較於傳統的擷取方式減少許多。而由此篇論文所提出的新擷取方法也可以結合其他的擷取方法，進而達到改善其效能的目的，例如：降低處理時間或是增加擷取增益。另外，此新擷取方法不僅可以透過結合兩個或兩個GPS L1 C/A 碼去擷取訊號，也可以結合GPS L1 C/A碼以及GIOVE-A L1B BOC(1,1)碼同時去擷取訊號。同時在論文中，將會介紹此擷取方法的基本概念，以及展示利用透過軟體接收器所接收到的中頻資料的擷取結果。經由這些實驗擷的的圖表數據顯示，此一方法確實能擷取兩個或兩個以上的訊號，其中包括GPS L1 和GIOVE-A L1B的訊號。

The receiver needs to take more processing time to process acquisition because there are more and more satellites transmitting the GNSS (Global Navigation Satellite System) signal. This paper purpose a new acquisition method to acquire two or more GPS L1 signal, and this new method needs the processing time less than the conventional acquisition method. This new method purposed by this paper can combine with the other acquisition methods to improve the performance like the reduction of the processing time or the increment of the processing gain. This new acquisition method not only can combine two or more GPS L1 C/A codes but also GPS L1 C/A code and GIOVE-A L1B BOC(1,1) code to acquire the received signal at the same time. This paper will show the concept of this new acquisition method and the experiment result produced by acquiring the raw IF data received by the software receiver. As shown in the figures and tables of the experiment result, this new method can acquire two or more signals including GPS L1 and GIOVE-A L1B.

[1] Kaplan, E.D., Understanding GPS: principles and application, Artech House Publishers, Boston, MA, 1996
[2] Pratap Misra, Per Enge, Global Positioning System: Signals, Measurements, and Performance Second Edition, Ganga-Jamuna Press, Lincoln, 2006
[3] Sherman Lo, Alan Chen, Per Enge, Grace Gao, Dennis Akos, Jean-Luc Issler, Lionelries, Thomas Grelier, Joel Dantepal, “GNSS Album: Images and Spectral Signatures of the New GNSS Signals, “ InsideGNSS, MAY/JUNE 2006, pp. 46-56
[4] Grace Xingxin Gao, Jim Spilker, Todd Walter, Per Enge and Anthony R Pratt, ”Code Generation Scheme and property Analysis of Broadcast Galileo L1 and E6 Signal,” Proceedings on ION GPS/GNSS 2006, Fort Worth, TX, September, 2006
[5] Kai Borre, Dennis M. Akos, A Software-Defined GPS and Galileo Receiver – A Single-Frequency Approach, Birkäuser Boston, NY, 2007
[6] NordNav Technologies AB, Software Installation and Operation Manual, Luleå, Sweden, 2006
[7] Alan V. Oppenheim, Ronald W. Schafer, Discrete-time signal processing, Prentice Hall International, Inc., NJ, 1989
[8] Mark L. Psiaki, “Block Acquisition of Weak GPS Signals in a Software Receiver,” Proceedings on ION GPS 2001, Salt Lake City, UT, September, 2001
[9] Yao-Cheng Lin, Shau-Shiun Jan, “Multi-C/A Code Acquisition Method,” Proceedings on ION NTM 2007, Catamaran Resort Hotel, San Diego, California, January, 2007
[10] GPS Joint Program Office, “ICD-GPS-200 GPS Interface Control Document,” ARINC Research Corporation, 12 April 2000
[11] David M. Lin, James B. Y. Tsui, “Comparison of Acquisition Methods for Software GPS Receiver,” Proceedings on ION GPS 2000, 2000
[12] James Bao-Yen Tsui, Fundamentals of Global Positioning System Receivers - A Software Approach, John Wiley & Sons, Inc., Hoboken, NJ, 2005
[13] Rigas T. Ioannides, L. Enrique Aguado, Gary Brodin, “Coherent Integration of Future GNSS Signals”, Proceedings on ION GPS/GNSS 2006, Fort Worth, TX, September, 2006
[14] P.K. Sagiraju, S. Agaian and D. Akopian, “Reduced complexity acquisition of GPS signals for software embedded applications”, IEE Proc.-Radar Sonar Navig, Vol. 153, No. 1, February 2006