摘要
提出了一种基于卫星配对的北斗卫星导航系统扩频码优化分配方案。增加导航卫星和扩频码的数量是提高卫星导航系统性能的重要途径之一,扩频码数量的增加将导致扩频码相关性能降低和扩频码搜索时间的增加。基于北斗卫星导航系统导航卫星星座结构分析,提出了卫星配对的概念。卫星配对内的两颗卫星可以共用同一扩频码而不互相干扰,从而可以降低约50%的扩频码数量。以北斗卫星导航系统的空间信息号接口控制文件中B1I信号为实例,对新方法进行验证。结果表明,在不增加信号干扰的前提下,新方法只需要15个扩频码即可满足27颗中圆地球轨道卫星的要求,扩频码的互相关性改善1.3-1.7dB,接收机搜索扩频码的时间降低44%。
An optimized satellite-pair-based assignment scheme is proposed for spreading codes of BeiDou navigation satellite system(BDS)in this paper.Using more navigation satellites and spread codes is a very important routine to improve the performance of satellite navigation system.The routine results in two things:worse cross-correlation function of spreading codes and more time of searching for the spreading code.The concept of satellite-pair is defined based on navigation satellite constellation analysis.The two satellites of a satellite-pair could share the same spreading code without interfering to each other.The new code assigning method can reduce about 50%spread codes in a navigation system.A test case of the new method is given based on BDS B1Isignal defined in interface control document(ICD).The results show that only 15spreading codes are required for 27medium earth orbit(MEO)satellites without increasing the signal interference.The cross-correlation functions of the spreading codes obtain an improvement of 1.3to 1.7dB.The new method reduces 44%time of navigation receiver searching for spreading codes.
出处
《导航定位学报》
2013年第3期39-42,共4页
Journal of Navigation and Positioning
基金
国家863课题(2011AA20502)
