一种新的导航系统仿真轨迹设计方法

飞行轨迹动态参数是验证捷联惯导系统、组合导航系统等算法有效性的重要依据。利用飞行控制原理设计了一种通用的飞机飞行仿真轨迹,并在Visual Studio 2005开发环境下设计了飞行轨迹仿真软件。该仿真软件产生的数据有效地测试了某型导航系统导航参数的误差精度,验证了捷联惯导算法的正确性。     

指北式捷联惯导系统软件的仿真与测试

传统测试用飞行轨迹侧重于模拟飞机真实的飞行轨迹,其导航算法的局限性使得即使出现大的误差也可能无法察觉.改进了一种解析式测试用飞行轨迹的生成方法,设计了一条飞行仿真轨迹,并对轨迹进行了性能分析,指出了方法与传统的飞行轨迹设计方法的优劣.在指北式捷联惯导系统中,对惯性器件进行了建模并设计了惯导系统仿真软件.用所生成的飞行仿真轨迹对导航系统软件进行了测试.通过仿真比较,有效地验证了导航软件的正确性和可靠性.     

游移方位捷联惯导系统软件测试与仿真

用C语言实现了游移方位捷联惯导系统的实时软件仿真;分别以圆球和参考旋转椭球体作为地球模型进行导航参数计算;用圆球模型下的飞行轨迹数据对圆球模型,椭球模型,加惯性元件误差的椭球模型下的捷联惯导系统导航参数进行测试;提出将速度通道和高度通道联立求解的方法.以提高速度,高度计算的准确性;并解决了导航参数解算中出现的计算周期同步问题;分析了误差来源,比较了圆球和参考旋转椭球体之间的差异;验证了该惯导系统仿真的正确性,证明了该测试方法的可行性。     

飞机飞行轨迹仿真系统设计与实现

捷联惯导软件测试中,一般难以得到真实的航迹数据和飞行器的各种参数,针对要获得飞行轨迹数据和惯性器件输出参数,设计飞行轨迹仿真系统利用LabVIEW虚拟平台,将战斗机各种典型的飞行动作进行模块化处理,自由组合成一条飞行轨迹用于实时仿真测试.系统中的轨迹建模以几何算法为主,避免了采用差分算法时产生的计算误差,实现飞行航迹各参数的实时动态显示.对飞行中空气阻力对轨迹的影响进行了分析,加入空气阻力并建立新的模型,得到误差曲线.实验结果表明,系统能够实现轨迹的动态特性,同时空气阻力的影响也与理论相符,可以得到有用测试数据.     

捷联惯导系统测试中仿真轨迹的设计与分析

由于很难获得全面真实的导航飞行轨迹数据,而各类导航系统性能测试又必须要有飞行轨迹数据和惯性器件的输出参数.针对捷联惯性导航系统进行测试的飞机仿真飞行轨迹的设计方法.方法将飞行轨迹分解成若干任务段,根据实际需要,通过自由组合这些任务段,得到一条完整的飞行轨迹.据此设计了一条仿真轨迹并对该轨迹进行了性能分析,结果表明设计方法不仅能够较好的模拟飞机的实际飞行状态,更能有效的检验捷联惯性导航算法的精确性和可靠性,应用效果令人满意.     

无人车捷联惯导系统仿真器设计

捷联惯导系统仿真模块的研究对于组合导航有着重要意义,为了检验该模块性能,在无人车轨迹模拟器的基础上分别基于方向余弦法与四元素法对捷联惯导系统仿真器进行了设计。首先基于运动学模型模拟无人车行驶的平面运动轨迹,并基于高斯投影反算原理求出该轨迹中各点所对应的经纬度信息作为真实值。基于该运动轨迹将对应的三维加速度与三维姿态角输入到捷联惯导系统仿真模块中,将求解出的经纬度作为计算值。将计算值与真实值进行比较,发现经纬度误差随时间而递增,三维姿态角误差随时间呈现周期性振荡,实际应用中有必要对误差进行相应的补偿。     

六加速度计的GFSINS/GPS组合导航系统研究

无陀螺捷联惯导系统(GFSINS)的角速度解算误差与加速度计测量误差紧密相天,加速度计测量误差会导致整个惯导系统导航参数随时问快速发散.针对这一问题,在传统捷联惯导系统的基础上,基于某种六加速度计配置方式,推导了尢陀螺捷联惯导系统误差方程,利用卡尔曼滤波器组成了GFSINS/GPS组合导航系统.经仿真验证,该组合导航系...     

通用惯导测试仿真系统的设计与实现

惯导性能测试一般在地面实验平台上进行,只能得到离散状态的测量结果,不能满足分析整个系统性能要求。建立飞行仿真系统能模拟各种飞行模态,并能够对惯导性能进行动态连续飞行轨迹下测试,在工程应用上具有重要意义。提出了惯导性能测试仿真系统的结构框架,并进行了系统功能分析与硬件设计,采用模块化设计思想,构造了基于控制律的飞控仿真模块及惯导反解算、通信等软件模块,给出了详细的设计及实现方法,并使用VC进行算法、系统实现。与惯导系统的联合仿真证明,为惯导测试系统的设计提供有效的平台。     

多惯组冗余系统安装误差的空中标定技术

以多组平行安装的捷联惯导构成的冗余系统为研究对象,提出了一种GPS辅助条件下惯导间安装误差的空中标定算法。该算法以其中一套惯导系统为安装基准,与GPS伪距、伪距率信息深组合后的导航结果为真实参考信息,标定前利用飞机机动提高基准惯导的姿态精度,标定开始时刻将基准惯导的导航信息装订给待标定惯导作为导航初值并进行姿态更新,利用待标定惯导的导航误差模型建立卡尔曼滤波器,量测量取为组合姿态与待标定惯导姿态的姿态误差,通过姿态匹配的方式对两套惯组之间安装误差进行标定。仿真结果显示,该方法不需要飞机做精确的角机动,只利用简单的摇翼和盘旋机动就可以对安装误差进行精确标定,且标定精度可达到角秒级水平。     

捷联惯导系统软件测试中的仿真飞行轨迹设计及应用

介绍了一种针对捷联惯性导航系统进行软件测试的仿真飞行轨迹的设计方法。该方法根据实际情况，将各种典型的机动动作做成了单个的模块；然后再根据需要测试的性能将各个机动动作自由组合成一条飞行轨迹进行实时仿真测试。笔者利用该飞行轨迹设计方法设计出一些典型的飞行轨迹并应用于我国某型捷联惯性导航系统的软件测试中，为系统性能、精度的提高作出了重大贡献。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.