北斗B1频点公开服务信号调制方式研究

在全球卫星导航系统中B1/L1频点（1575.42MHz）是互操作频点,GPS和Galileo系统在此频点设计了L1C和E1OS信号.在北斗导航系统第三阶段信号初步方案中在此频点的公开信号B1C设计为具有导频和数据通道的MBOC（6,1,1/11）（Multiplexed Binary Offset Carrier,简称为MBOC）调制方式,与L1C和E1OS具有互操作性,但是其兼容性、实现方式、导航性能还有待进一步研究.为此本文讨论了北斗B1C信号的设计原则,进而提出一种通道间复合的二进制码符号（Binary Coded Symbol,简称为BCS）调制方式（Composite Binary Coded Symbols between Channels,简称为CBCSC）.给出了一种具有良好性质的BCS调制码形,对比分析在此BCS调制基础上设计的CBCSC调制方案和MBOC的性能.根据分析得出的结论为CBCSC调制方式在兼容性、接收性能、实现复杂度等方面优于MBOC调制.

Research on Compass B1 open service signal modulation

In the Global Navigation Satellite Systems （GNSS）,B1/L1 frequency （1575.42 MHz） is one of the interoperability frequency bands.Specially,L1C and E1OS signals in the GPS and Galileo systems were designed on this frequency.In the initial program of the third phase of Compass navigation system,B1C signal is a MBOC （6,1,1/11） signal with pilot and data channels,which has the capacity to be interoperated with L1C and E1OS.However,its compatibility,implementation and performance should be deeply investigated.As such,this paper starts with the overall discussion of design principles of Compass B1C signal.Afterward,composite binary coded symbols （BCS） modulation between the channels modulation （CBCSC） are presented.A kind of BCS modulation which has good character is proposed,and then the two candidates for Compass B1C signal based on CBCSC modulation are compared with MBOC.The conclusion is that CBCSC outperforms MBOC in terms of compatibility,receiver performance,implementation complexity,etc.