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41.
多径是影响卫星定位系统的主要因素,因此如何消除多径成为提高定位精度的重要任务。以Galileo接收机为基础来研究多径的抑制。主要介绍了Galileo信号和多径信号的基本结构,通过对多径消除方法——窄相关技术的仿真,可以看出,窄相关技术对跟踪误差有很好的抑制能力,能提高测量精度。 相似文献
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伽利略导航系统将在E5频段发射交替二元偏置载波(Alternate Binary Offset Carrier,ALTBOC)信号,但国内外学者对其特性的研究还很不充分。基于随机信号分析理论,在对Galileo ALTBOC(15,10)信号各分量正交性证明基础上,提出采用多进制符号编码调制信号功率谱和正交信号功率谱公式推导Galileo ALTBOC信号的功率谱的新方法,并将其与传统双向偏移QPSK-R(10)信号功率谱近似算法进行比对,ALTBOC功率谱密度与双向偏移QPSK-R(10)功率谱密度最大差0.9 dB。 相似文献
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Hui Hua Chen Wei Min Jia Min Li Yao 《Wireless Communications and Mobile Computing》2014,14(15):1500-1508
Global Navigation Satellite Systems positioning accuracy indoor and urban canyons environments are greatly affected by multipath because of distortions in its autocorrelation function. In this paper, we propose a new multipath mitigation technique based on the concept of S‐curve shaping for the new alternative binary offset carrier (AltBOC)‐modulated signals, which will most likely be used in both European Galileo system and Chinese Compass system. The definition of an optimum S‐curve is employed to reduce the false lock points and to improve the multipath mitigation capability via determining the shape of the local code tracking reference function. The structure of the proposed code tracking loop for AltBOC signals is quite simple and only requires one complex correlator. Results demonstrate that the proposed technique provides superior multipath mitigation performance compared with the conventional receiver correlation techniques and removes the ambiguity completely. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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易翔 《电子信息对抗技术》2009,24(1):38-42
GalileoE1民用信号采用新的BOC(1,1)扩频调制方式。针对E1信号进行信号建模,并对其信号特征进行了详细研究,最后设计了Galileo软件解调器中的信号处理模块。通过仿真验证表明,软件解调器成功实现了对GalileoE1信号的捕获、跟踪、解扩、解调全过程处理,克服了BOC解调的错锁问题。 相似文献
46.
BOC调制作为一种导航信号体制,具有良好的抗多径和抗干扰性能,同时实现共用载波频率条件下的频谱分离。与BPSK调制信号相比,BOC调制信号具有多径误差小、码跟踪热噪声误差小的优点。通过对BOC调制技术和合路方式的深入分析,给出了各种BOC调制的自相关和功率谱函数,以及各种合路方式的分析比较。通过仿真验证了BOC信号的码跟踪性能和抗多径性能的优越性。 相似文献
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Maurizio Fantino Paolo Mulassano Fabio Dovis Letizia Lo Presti 《Wireless Personal Communications》2008,44(3):323-339
In the framework of the modernization plans of Global Navigation Satellite Systems (GNSS) a new Multiplexed Binary Offset
Carrier (MBOC) modulation has been proposed as a possible Signal-In-Space (SIS) with improved performance with respect to
the robustness against external sources of degradation. Discussion around such signal format are still on-going at the time
of writing, anyway it is the most probable candidate signal that will be adopted by both GPS L1C and the Galileo E1 Open Service
(OS) signals [(, 2004)] as modernization of the present BOC(1,1). In the context of the integration between wireless communication and satellite
navigation, one of the major problems is that usually the GNSS receiver has to work in a critical environment characterized
by a heavy presence of multipath or interference sources. Some examples are urban canyons or light indoor spaces. These are
also typical situations for the usage of personal communications systems. The new MBOC modulation have been studied with the
specific goal to create a signal more robust with respect to multipath, bringing the high performance of Galileo in situations
in which the present BOC(1,1) shows limitations. In this sense, future Location Based Services (LBS) provided on the basis
of the GNSS OS will benefits from this intrinsic robustness of the signal. Throughout the paper a review of the MBOC structure
will be presented, specifying that in the Galileo framework such a structure has been proposed in a version named Composite
BOC (CBOC). In particular, the paper presents the simulation of the CBOC behavior in presence of multipath showing the extreme
improvement with respect to other BOC solutions.
相似文献
Letizia Lo PrestiEmail: |
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设计并实现了一种适用于SBAS和Galileo卫星导航系统的(2,1,7)卷积码的Viterbi译码器.由于卫星导航系统中的数据率不高,采用串行结构实现 Viterbi译码器,并且多通道复用同一译码器,以节省电路面积.此外,采用改进的加比选单元并通过寄存器交换法对幸存路径进行管理,以进一步优化电路结构.为了减少RA M 的使用,利用同址更新技术将路径度量累加值和幸存路径存储至RAM .译码电路通过FPGA验证,采用SMIC65 nm工艺库进行综合,该译码器逻辑电路的面积为4738μm2. 相似文献