摘要
为提高新一代北斗无线电测定卫星服务在有限带宽内的信息服务容量,借鉴了正交频分复用的理念,新体制无线电测定卫星服务信号设计采用多个子载波进行信号调制。以往针对多用户的分析主要考虑多址干扰,对载波频偏损耗和伪码损耗单独考虑,这不能解释新体制调制在相同的同步头的情况下其他子载波上信号在当前观测子载波上形成较大相关峰的问题,该问题对信号接收产生较大干扰。本文对该问题产生机理进行了分析,并提出了两种相关干扰的消除方法。
In order to increase the message volume in limited bandwidth for new generation BDS( BeiDou navigation satellite system) RDSS( radio determination satellite service),the signal was modulated on multi-subcarriers inferring to orthogonal frequency division multiplexing.Modulation on multi-subcarriers was rarely used in navigation systems. Corresponding analysis mainly focuses on multiple access affection,and loss caused by carrier frequency offset and code phase offset were analyzed separately. It is not considered that when using the same synchronization head,the signals on other subcarriers can cause high correlation peak for the observed subcarrier. This may affect the receiving of signals. The mechanism is analyzed and two correlation mitigation methods are supplied,which offers certain guidance for the design of the follow-up system.
引文
[1]Kaplan E D,Hegarty C J. GPS原理与应用[M]. 2版.寇艳红,译.北京:电子工业出版社,2012.Kaplan E D,Hegarty C J. Understanding GPS:principles and applications[M]. 2nd ed. Translated by KOU Yanhong.Beijing:Publishing House of Electronics Industry,2012.(in Chinese)
[2]谢钢. GPS原理与接收机设计[M].北京:电子工业出版社,2012.XIE Gang. Principles of GPS and receiver design[M].Beijing:Publishing House of Electronics Industry,2012.(in Chinese)
[3]谭述森.北斗卫星导航系统的发展与思考[J].宇航学报,2008,29(2):391-396.TAN Shusen. Development and thought of compass navigation satellite system[J]. Journal of Astronautics,2008,29(2):391-396.(in Chinese)
[4]李井源.卫星导航系统多址干扰影响分析及其抑制技术研究[D].长沙:国防科技大学,2015.LI Jingyuan. Research on multiple-access interference effects and mitigation techniques in satellite navigation systems[D].Changsha:National University of Defense Technology,2015.(in Chinese)
[5]Betz J W,Kolodziejski K R. Generalized theory of code tracking with an early-late discriminator partⅠ:lower bound and coherent processing[J]. IEEE Transactions on Aerospace and Electronic Systems,2009,45(4):1538-1550.
[6]李春霞.高动态条件下伪码相关特性及其应用研究[D].长沙:国防科技大学,2005.LI Chunxia. The characteristics of PN code correlation and its applications under high dynamics[D]. Changsha:National University of Defense Technology,2005.(in Chinese)
[7]王雷. GPS L2C信号捕获跟踪技术研究[D].长沙:国防科技大学,2016.WANG Lei. Research on GPS L2C acquisition and tracking algorithms[D]. Changsha:National University of Defense Technology,2016.(in Chinese)
[8]Glennon E P,Dempster A G. Cross correlation mitigation by adaptive orthogonalization using constraints-new results[C]//Proceedings of the 19th International Technical Meeting of the Satellite Division of the Institute of Navigation,2006:1811-1820.
[9]Betz J W,Kolodziejski K R. Generalized theory of code tracking with an early-late discriminator part II:noncoherent processing and numerical results[J]. IEEE Transactions on Aerospace and Electronic Systems,2009,45(4):1557-1564.
[10]Xu C T,Liu Z,Tang X M,et al. A design method of code correlation reference waveform in GNSS based on least-squares fitting[J]. Sensors,2016,16(8):1194.