一种基于相位差分的GPS比特同步方法

GPS bit synchronization based on phase difference

为了解决较大频偏下GPS导航信号的比特同步问题,提出了一种基于相位差分的比特同步方法.通过对相关器输出的相邻数据的相位差分进行统计,得到相位差分最大的位置,即比特边界的位置,从而实现比特同步.采用频偏补偿的方式对同步方法进行优化,较大地提高了在极大频偏下的比特同步性能,并且可以同时得到信号的精确频偏估计.经过理论推导和仿真验证,该方法不仅在频率同步的情况下具有很好的检测性能,而且解决了以往方法在频率未同步的情况下无法进行比特同步的问题.

A new bit synchronization method based on phase difference was proposed to achieve bit synchronization of the signals from global position system （GPS） satellites in high frequency offset. The method analyzes the phase difference between adjacent correlations, and finds out the bit boundary position where a maximal phase difference is detected. Furthermore, the method is optimized to improve the bit synchronization performance in extra high frequency offset by frequency compensation, and the optimized method can get the precise frequency estimation simultaneously. Analysis and simulation showed that the method not only has good performance in frequency synchronized situation, but also solves the GPS bit synchronization problem with high frequency offset.