【作者】 牛满仓； 战兴群； 刘卫； 刘莉；

【Author】 Mancang Niu~1,Xingqun Zhan~1,Wei Liu~1,Li Liu~1 1 School of Aeronautics and Astronautics,Shanghai Jiao Tong University,Shanghai,China

【机构】 上海交通大学航空航天学院；

【摘要】 在码分多址卫星导航系统中,用户接收机利用各个卫星导航信号包含的扩频码区分不同卫星实现导航定位,另外,在L1频段民用信号上,GPS,Galileo和北斗卫星导航系统均采用具有相同功率谱密度分布的MBOC(6,1,1/11)调制方式,引起三大导航系统信号扩频码间的相互干扰。因此设计出具有良好性能的卫星导航系统扩频码对提高系统导航定位精度,确保与其它导航系统扩频码的兼容都有重要意义。本文首先介绍了构造卫星导航信号扩频码的常见伪随机序列,包括m序列,Gold序列,Kasami大、小集合序列,Weil序列,内存码(random codes)等的生成原理和构造方法。然后分别仿真生成了Kasami序列,基于Go1d序列,Weil序列的GPS C/A码和GPS L1C信号扩频码,基于内存码(randomcodes)的Galileo E1 OS和E6 CS信号扩频码,并对其奇偶自,互相关特性进行仿真分析。最后对比分析该四种扩频码码族大小,码长灵活性,奇偶自,互相关,实现难易程度等特性后,发现基于Weil序列生成的卫星导航信号扩频码奇偶自,互相关特性良好,易于工程实现,适宜在现代化卫星导航系统中使用。更多还原

【Abstract】 The receivers in the Code Division Multiple Access(CDMA) satellite navigation system use the spreading codes of satellite navigation signal to distinguish different satellites and so as to achieve the navigation and positioning.On the other hand,GPS,Galileo,and BEIDOU satellite navigation system have all adopted the identical power spectral density of MBOC(6,1,1/11) at the L1 Civil signal which result to spreading code interference among the three navigation systems.Hence,designing spreading codes with good performance has significant meaning to both the improvement of navigation and positioning accuracy and spreading codes compatibility to other navigation systems.The generation and construction of normal Pseudo Random Noise(PRN) sequences to construct satellite navigation signal spreading codes,including m sequence,Gold sequence,Kasami sequence with big and small set,Weil sequence and random codes,are firstly introduced.Then Kasami sequence,GPS L1C and Galileo E1 OS and E6 CS spreading codes each based on Weil sequence and random codes are generated separately,auto and cross correlation in even and odd case of which are analyzed simultaneously.Finally,comparison analysis about code family size,code length flexibility,auto and cross correlation in even and odd case,and implementation difficulty grade are conducted.It is obvious that spreading codes based on Weil sequence have better auto and cross correlation in even and odd case,and easy to implement in the engineering.Therefore,the Weil sequence has potential application in future satellite navigation system.更多还原