Toward a richer view of the scientific method: The role of conceptual analysis.

Within the complex set of activities that comprise the scientific method, three clusters of activities can be recognized: experimentation, mathematization, and conceptual analysis. In psychology, the first two of these clusters are well-known and valued, but the third seems less known and valued. The authors show the value of these three clusters of scientific method activities in the works of the quintessential scientist Galileo Galilei. They then illustrate how conceptual analysis can be used in psychology to clarify the grammar and meaning of concepts, expose conceptual problems in models, reveal unacknowledged assumptions and steps in arguments, and evaluate the consistency of theoretical accounts. The article concludes with a discussion of three criticisms of conceptual analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A deterministic electron, photon, proton and heavy ion transport suite for the study of the Jovian moon Europa

A Langley research center (LaRC) developed deterministic suite of radiation transport codes describing the propagation of electron, photon, proton and heavy ion in condensed media is used to simulate the exposure from the spectral distribution of the aforementioned particles in the Jovian radiation environment. Based on the measurements by the Galileo probe (1995-2003) heavy ion counter (HIC), the choice of trapped heavy ions is limited to carbon, oxygen and sulfur (COS). The deterministic particle transport suite consists of a coupled electron photon algorithm (CEPTRN) and a coupled light heavy ion algorithm (HZETRN). The primary purpose for the development of the transport suite is to provide a means to the spacecraft design community to rapidly perform numerous repetitive calculations essential for electron, photon, proton and heavy ion exposure assessment in a complex space structure. In this paper, the reference radiation environment of the Galilean satellite Europa is used as a representative boundary condition to show the capabilities of the transport suite. While the transport suite can directly access the output electron and proton spectra of the Jovian environment as generated by the jet propulsion laboratory (JPL) Galileo interim radiation electron (GIRE) model of 2003; for the sake of relevance to the upcoming Europa Jupiter system mission (EJSM), the JPL provided Europa mission fluence spectrum, is used to produce the corresponding depth dose curve in silicon behind a default aluminum shield of 100 mils (∼0.7 g/cm²). The transport suite can also accept a geometry describing ray traced thickness file from a computer aided design (CAD) package and calculate the total ionizing dose (TID) at a specific target point within the interior of the vehicle. In that regard, using a low fidelity CAD model of the Galileo probe generated by the authors, the transport suite was verified versus Monte Carlo (MC) simulation for orbits JOI-J35 of the Galileo probe extended mission. For the upcoming EJSM mission with an expected launch date of 2020, the transport suite is used to compute the depth dose profile for the traditional aluminum silicon as a standard shield target combination, as well as simulating the shielding response of a high charge number (Z) material such as tantalum (Ta). Finally, a shield optimization algorithm is discussed which can guide the instrument designers and fabrication personnel with the choice of graded-Z shield selection and analysis.     

夯实北斗卫星导航系统鼎立基础的建议

介绍了GPS、GLONASS、Galileo和北斗四大系统的发展近况,提出了务实北斗卫星导航系统鼎立基础的建议。     

Galileo接收机中窄相关技术的分析与研究

将窄相关技术应用到Galileo系统中进行分析和研究具有非常实际的意义。主要介绍了Galileo信号的基本结构,根据延迟锁相环的基本结构分析了其多径误差函数。通过对跟踪误差函数方差的仿真分析,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。     

伽利略伪卫星脉冲调制方案最优化研究

概述并评估了已有的几种关于GPS的脉冲图案和脉冲调制技术。由于Galileo和GPS在信号结构方面的不同,在Galileo中这些脉冲方案不能直接被采用,所以必须研究和确立新的脉冲方案方式和脉冲图案。讨论并研究了脉冲方案方法的各个要素,完成了基于Galileo信号结构(伪码,码速率,互相关性)的仿真研究并对结果进行了分析。通过仿真确立了脉冲调制的几个关键要素,并由此研究设计了一种新的Galileo伪卫星脉冲优化方案。     

基于多载波定位系统的模糊度算法研究

采用了多载波定位技术提高定位精度的原理,建立了系统的数学模型,在此基础上模拟仿真了静态情况下GPS系统采用2和3个载波,G alileo系统采用2、3和4个载波定位时,模糊度的平均建立时间和均方差随基线长度变化的关系。证明了采用多载波定位的效果优于双载波定位的效果,给出了仿真结果。     

兼容GPS/Galileo系统单频接收机的研究

为了提高全球定位系统接收机定位精度的可靠性,研究了一种基于Xilinx公司的FPGA和Intel公司奔腾处理器的民用接收机．该接收机可以接收处理GPS／Galileo两个系统L1频段内所有民用信号,这样即使Intel公司GPS的粗码信号受到人为或者其它因素的干扰,接收机也能接收到来自Galileo系统的开放信号来保证用户的定位精度,而不至于影响用户的使用．结果表明,兼容两个系统的接收机不仅能提高用户定位精度的可靠性,而且有广泛的民用市场．     

BOC(1,1)信号的自适应捕获

GPS现代化以及Galileo系统都将使用BOC调制信号,与单纯的扩频码相比,BOC信号有更小的跟踪抖动和更好的抗多径性能,但因为BOC信号自相关函数具有多峰性,使得捕获更具挑战性,跟踪时容易锁在假峰上.Julien提出的合成相关捕获算法完全删除了BOC(n,n)信号的边峰,保持主峰不变,因此不需要检查跟踪是否在主峰上.在此基础上推导了一种自适应捕获算法,在保证系统误捕率恒定的情况下,能根据接收卫星信号功率的不同自动的调整门限.     

基于高增益接收系统的Galileo E1信号质量评估方法研究

Galileo系统在E1频点采用Interplex调制方式播发导航信号,由于缺乏E1信号功率分配和伪码序列等先验信息,一般的研究人员只能开展有限的信号质量特性研究.针对该问题,提出一套基于高增益天线的空间信号质量评估方法,实现了E1授权信号的解析,完善了E1信号评估体系.运用相关功率法来解决信号分量功率比问题,采用跟踪结果解决相位偏差估计问题,提出加权组合平均和码相位平均相结合的新型时域波形分离方法,克服了电文和码多普勒对时域波形特性评估的影响,采用S曲线过零点偏差（S-curve offset Biases,SCB）等参数进行信号测距偏差定量评估.通过该方法对Galileo GSAT-0214卫星进行了评估,结果显示：该卫星E1各信号分量SCB小于0.2ns,测距性能优异,其复用效率达到了97.8%,优于GPS L1信号和北斗三号系统（BDS-3） B1信号.     

伪卫星环境下的Galileo测试接收机通道结构设计

为了消除由于伪卫星测试环境下造成的远近效应,该文提出了一种基于SIC算法原理的伽利略测试接收机通道结构设计,利用伪卫星通道的跟踪结果生成强干扰信号用以抵消GPS和Galileo通道的输入信号的强干扰信号成分,并且伪卫星通道对较强的伪卫星信号使用1/8个周期的伪随机码做相关运算的方法,以牺牲9dB信噪比的代价使信号捕获时间大大缩短。Matlab仿真结果表明能很好地消除远近效应,并能加快伪卫星信号的捕获。