一种GPS/Galileo双模双频接收机射频前端芯片设计

提出了一种双频带混合GPS/Galileo接收系统,GPS与Galileo共同运作,规避了单一模式的安全漏洞,使卫星定位提供更稳定、更可靠、更安全的导航服务成为可能.接收系统同时接收GPS L1/L2和Galileo E1/E5a信号,提高了系统灵敏度,可以实现高精度定位和实时导航定位,同时能够最大限度地复用射频硬件资源,大大减少了芯片面积的消耗和系统功耗.通过系统参数仿真,各系统性能指标均满足设计要求.     

Jesuit Science After Galileo: The Cosmology of Gabriele Beati

Abstract.   Gabriele Beati (1607–1673) taught mathematics at the Collegio Romano when in 1662 he published an introduction to astronomy, the Sphaera triplex . This little work contains an interesting cosmic section which is analyzed here as representing a fusion of Jesuit traditions in cosmology achieved by Giovanni Battista Riccioli (1598–1671). The cosmic section enumerates three heavens, depicts fluid planetary heavens, and expresses hexameral biblical idiom. Woodcut and engraved variants of the cosmic section offer a glimpse of Jesuit freedom to experiment with various cosmological systems (Capellan, Tychonic and semi-Tychonic). Analysis of this cosmic section suggests several conclusions for the interpretation of visual representations, science and biblical interpretation, the Scientific Revolution and Jesuit science after Galileo.     

基于FPGA的Galileo/GPS伪卫星基带调制设计与实现

根据Galileo/GPS伪卫星综合基带子系统的功能要求, 提出一种基于FPGA的设计方案.其主要功能有产生扩频伪码、完成Galileo OS SIS ICD中L1波段、E5a波段、E5b波段及E1波段的各种信号调制方式并与单片机进行通信完成导航数据的加载及监控信息的应答.测试结果表明: 该方案完全满足系统的设计要求.     

Performance of the Proposed Galileo CBOC Modulation in Heavy Multipath Environment

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.

GalileoE1信号特征及其软件解调

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。     

Galileo接收机的多径误差分析与研究

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。     

GPS L5并行码相位捕获算法仿真分析

GPS L5信号是GPS现代化中一个新的民用信号。基于此,从Galileo信号及其捕获算法的简单分析引入GPS L5信号并行码相位搜索的研究,并对GPS L5信号的捕获进行仿真分析。通过研究表明,在GPS L5并行码信号捕获中,双信道并行码相位搜索算法的捕获能力最强但计算量最大。pilot channel并行码相位搜索算法的计算量与data channel并行码相位搜索算法的计算量相同,但捕获能力比双信道并行码相位搜索算法强。     

How to enrich scientific method.

Comments on an article (see record 2007-14606-004) by A. Machado and F. J. Silva, who claimed that psychology's current conception of scientific method comprises two clusters of activities: experimentation and mathematization. They proposed that psychology needs to enrich its accounts of scientific method with a third cluster of activities that they call conceptual analysis. Haig agrees with the authors that psychology needs to improve its understanding of scientific methods, but he believes that giving greater attention to conceptual analysis is not the appropriate way to do this. In this comment, Haig suggests that conceptual analysis as such is not a distinctive feature of scientific method. He maintains instead that the most appropriate way to enrich our understanding of scientific method is to develop better theories of scientific method. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Galileo双频接收机及其关键模块的设计

为设计Galileo双频接收机,对Galileo系统空间信号的特性进行了描述,通过比较Galileo系统与GPS的不同,论述了Galileo系统的优点。最终再结合已有接收机技术,给出了一种实用的基于E5频段Galileo双频接收机结构体系的设计,并重点分析了下变频模块和信号捕获与跟踪模块的设计。     

GPS/Galileo组合导航定位系统中的选星算法

为解决双卫星组合导航系统定位精度与计算负担之间的矛盾,采用选星的改进措施,文中分析了双星座系统与单星座系统的区别,提出了常用的几种选取5颗星的方法,并分别进行仿真分析,总结出各自的优缺点.同时根据观测矩阵与GDOP值的关系提出选取大于5颗可见星的最大行列式绝对值法,并分别对选取6、7颗可见星进行仿真分析,由仿真结果可见此法的实用性.