脉冲星导航中最优脉冲星组合选取方法

分析了X射线脉冲星导航原理,发现脉冲星的位置和脉冲到达时间(Time of Arrival,TOA)的测量误差直接影响导航精度.为优选导航脉冲星组合,在误差协方差分析的基础上,提出了一种导航脉冲星组合优选方法.该方法分别定义了优选指标位置精度因子(Positioning Dilution of Precision,PDOP)和脉冲星优选指标(Pulsars Select Criteria,PSC),不仅考虑了脉冲星空间位置分布,还考虑了测量噪声差异对导航误差的影响.最后以25颗信号品质较好的脉冲星为例,仿真验证了所提方法的有效性.     

基于工作视角的性能放行在《飞机性能工程》课程中的实践化改革探索

根据交通运输专业《飞机性能工程》课程实践性强的特点,本文阐述了什么是性能放行,结合教学实际,介绍了在飞机性能工程教学中引入性能放行教学模式的思路,并以实例说明性能放行在飞机性能工程课程实践教学中的具体应用,以及应注意的问题。     

实对称区间矩阵的特征值边界逼近

针对实对称区间矩阵的特征值问题,从特征值区间估计出发,给出一种求解特征值区间下确界和上确界的逼近方法,对于研究包含不确定性的结构振动特性、系统稳定性和系统控制等工程设计与分析问题具有重要意义.     

加强螺纹和普通螺纹连接配合问题探讨

概述了螺纹在航空发动机中的应用现状,分析了异型螺纹的几种连接配合情况。     

一种自整定模糊PID型控制器

本文提出一种简单的模糊PID型控制器,分析了其结构组成,介绍了基于自整定量化因子的参数整定方法,并利用小增益定理对BIBO系统的稳定性进行了研究.仿真结果表明这种控制系统的性能优于线性PID控制器.     

双锥—圆筒红外辐射源特性的蒙特卡罗解

本文考虑了红外辐射源腔内的镜反射成份,采用镜-漫混合反射模式,用蒙特卡罗法求定空腔的定向有效发射率。在通解的数学模型基础上,还针对500K双锥-圆筒热管空腔求得其典型解,分析了空腔辐射特性与锥角的关系。利用本文提供的方法也可计算其他腔形的辐射特性。     

USB闪盘的软硬件开发技术

本文重点介绍了一种在USB接口下的闪盘（闪存编程器）的软硬件开发技术，对USB和闪存做了简单介绍，闪存在计算机、智能仪器、通信设备等中使用非常广泛，用于存放相对固定及便于升级的内容,闪盘因其存储容量大、体积小便于携带等优点，很快会代软驱软盘成为主要的移动存储器。USB作为一种新型的接口技术，以其简单易用、速度快、兼容性强等特点而倍受青睐。     

A study of long-term climatology of ionospheric irregularities by using GPS phase fluctuations at the Brazilian longitudes

We have examined the ionospheric plasma irregularities that were recorded by using three ground-based receivers of the global positioning system (GPS) located at Brazilian longitudes during the period of a complete solar cycle, 1995–2005. The statistic results show that ionospheric irregularities are very easy to occur in December solstice months but rare to occur in June solstice months. Besides, the occurrence rates of irregularities in both December and June solstice months are little dependent on solar activity. However, in equinoctial months, the development of irregularities is obviously dependent on solar activity. There is a new finding in this study that if strong irregularities are distinguished from moderate ones, their occurrence rates would increase with solar activity during the December solstice months.     

Track Association for Dynamic Target Tracking System Based on AP Algorithm

Track association of multi-target has been recognized as one of the key technologies in distributed multiple-sensor data fusion system,and its accuracy directly impacts on the performance of the whole tracking system.A multi-sensor data association is proposed based on aftinity propagation(AP)algorithm.The proposed method needs an initial similarity,a distance between any two points,as a parameter,therefore,the similarity matrix is calculated by track position,velocity and azimuth of track data.The approach can automatically obtain the optimal classification of uncertain target based on clustering validity index.Furthermore,the same kind of data are fused based on the variance of measured data and the fusion result can be taken as a new measured data of the target.Finally,the measured data are classified to a certain target based on the nearest neighbor ideas and its characteristics,then filtering and target tracking are conducted.The experimental results show that the proposed method can effectively achieve multi-sensor and multi-target track association.