【摘要】 伽利略卫星通信系统中主要由C/A码、P码、M码来实现导航定位,其中关键的就是C/A码。相对P码、M码来说,C/A码精度较低且编码格式公开,而面向民用时,P码格式还未公开,且对P码进行捕获时也是建立在先捕获C/A码上的,因此主要针对C/A码进行了仿真研究。在C/A码生成和调制仿真的基础上,进行了C/A码捕获的传统自相关方法研究,从算法的角度提出一种基于FFT的C/A码快捕方案的改进,减少了捕获的计算时间。并在加噪情况下对捕获方法进行仿真,进一步证实了改进方法的可行性,为P码的捕获研究提供了有效参考依据。更多还原

【Abstract】 There are three codes in Galileo system:the Coarse Access (C/A) code,the Precise (P) code,the M code. The key of Galileo System is the Coarse Access (C/A) code. Although the accuracy of the C/A code is lower than the Precise (P) code,the format of C/A code is open. But the Pcode isn’t open to the civil usage,and the Pcode acquisition also establishes the earlier C/A code acquisition. Therefore it aims at the research of the C/A code. Simulate the C/A code generation,modulation and acquisition. The acquisition scheme based on FFT is also provided and improved this method,reduced the acquired time. The performance at the noisy situation is very well which used improved way,and it also provided helpful information for the Pcode acquisition.更多还原