三视场定位定向设备的视场确定

为了提高三视场定位定向设备可靠性,建立三视场系统功能的基本约束条件测试模型,以模型为依据对可见光波段的视场进行优化分析。首先,分析了设备正常完成工作时采用组合星图识别和简单星图识别所需的必要条件,并建立这两种识别方式关于视场大小的概率分布模型。从原理和实验数据两个方面说明了三视场结构识别三角形概率分布不能通过单视场的概率分布简单推导获取的原因。,给出用蒙特卡洛法求取此概率分布和视场最优值的方法。然后,通过仿真分析得出了两种识别方法关于视场大小的概率分布,在分析两种识别方法仿真数据的基础上,取识别概率为1时视场大小为其优化值。实验结果表明:以组合星图识别为工作基础的三视场定位定向设备有更好的可靠性,优化的视场大小为4.2253.168 75。它满足三视场定位定向设备识别条件可靠性要求。     

GPS空间定位误差对平面位置的影响分析

GPS车辆导航中的地图匹配数据处理，首先是将GPS定位成果投影到高斯平面，然后将其转换为当地坐标系下的平面坐标。平面坐标的精度与这一过程关系甚密．本文推导了GPS空间定位误差对当地平面坐标成果的影响模型。     

CCD星敏感器在天文导航系统中的应用

本文介绍了基于星图匹配技术的新一代大视场天文导航原理和CCD星敏感器的基本工作原理,并对导航的精度做出理论计算,可适用于空中飞行器、舰船、陆用战车等武器装备,是天文导航今后的发展方向。     

基于不确定度的最小二乘法在天文定位计算中的应用

介绍不确定度估算在天文定位最小二乘法数据处理中的应用。实际应用证明，不确度概念的引用，使得天文定位中的数据处理更加科学，可靠度得到有效的提高。     

LOFIX定位误差分析

LOFIX是被动全向声呐最主要的定位方法,然而其精度和稳健性受到很多环境因素的影响。从理论上分析说明了各种因素的影响,并给出了这些因素的计算机仿真,为如何改善LOFIX定位误差提供了一定的理论依据,对实际的工程应用也有一定的借鉴意义。     

卫星干扰源定位中的误差分析与预测

卫星干扰源定位系统可以通过测量两颗卫星对干扰源形成的时差（DTO）和频差（DFO）来完成对未知干扰源的定位,其定位误差除了与时差、频差等参数测量值有关外,还和随时间变化的卫星星历有密切的关系。针对这一问题,首次提出了利用星历时变性特点来提高定位精度的新方法,该方法通过预测的定位误差来选择定位的最佳时刻,通过整合多次最佳时刻的定位结果来获得最小的定位误差。仿真表明,相对于传统的定位方法,这种新方法可以取得优于一个数量级的定位精度改善。     

一种天文／惯性／GPS／激光测距组合应用方案分析

S938昼夜星体跟踪器加装激光测距仪，构成一种天文／惯性／GPS激光测距的组合测量基准，以达到精确天文定位、精确差分GPS定位、精确天文定向、测岸标定向、测量船的东向速度、北向速度和合成速度以及激光测距和观察海空目标的目的。文中还进行了系统原理描述和误差分析与工程实现可行性分析。     

机载雷达组网导航定位误差仿真分析

机载雷达组网具有雷达组网和空中机动的综合优势.获取组网中载机导航定位的准确数据是目标定位的一个重要问题.文中对机载雷达组网时导航定位误差影响目标定位的误差机理进行了理论推导,重点对导航定位误差产生的目标定位误差进行了仿真分析,得出了两者之间的对应关系及导航定位误差产生的目标定位不一致性这一不可忽略的重要结论.     

基于被动定向与主动全向浮标的定位误差分析

航空反潜作为一种重要的反潜手段,在实战环境中得到了广泛的应用。声呐浮标是航空反潜的主要利器,提出一种新的浮标对目标定位的办法。在实际运用中,浮标存在测向误差和测距误差。仿真模拟发现,被动定向浮标的测向误差主要影响目标定位的y方向,主动全向浮标的测距误差主要影响目标定位的x方向。所构建的浮标和目标态势有利于今后联合使用多种类型浮标的综合战场环境分析。     

远程目标定位误差分析

采用光电跟踪器被动跟踪信息,实现远程目标的精确定位.对远程目标进行定位采用了中继定位方法.通过对中继站定位方法及其误差分析,提出了采用函数误差传递模型对定位误差进行计算.     

基于空间位置的增量式光电编码器误差检测系统

增量式光电编码器输出信号的正交性和均匀性是其重要技术指标之一,对增量式光电编码器的精度检测是编码器研制和生产过程中的重要环节。传统信号质量的检测是基于时间位置进行检测的,其检测准确度受转速均匀度影响,在高速、变速转动下对增量式光电编码器的动态性能检测并不准确。提出了一种基于空间位置的信号质量检测方法,并设计了相应的检测系统。检测系统采用直流无刷电机带动高精度角脉冲发生器和被检增量式编码器同轴旋转,并采集高精度角脉冲发生器在被检增量式编码器输出信号边沿时刻的数值,进行误差计算。该检测系统极大地减小了由于转速不均匀造成的测量不准确度。运用该检测系统对输出脉冲周期数为32 400的增量式编码器进行检测,并与时间位置检测法进行对比实验。实验结果表明:该检测系统检测结果不受电机转速变化的影响,可有效地提高检测精度及检测效率,能够实现动态检测。该系统的研制为批量生产增量式光电编码器提供了极大的便捷。     

Error analysis for refractive-index profile determination fromnear-field measurements

Refractive-index profiles of diffused optical waveguides are determined by analyzing the near-field pattern of the waveguide. For this method, a computer simulation of measurement errors due to noise, quantization, defocusing, and nonlinearity of the camera system is presented by using data of a typical camera measurement system. The simulation procedure includes signal processing of the measurement intensity profile by means of a cubic spline approximation in order to reduce the influence of the measurement system errors. The residual errors associated with this technique are on the order of a few percent when measuring typical Ti:LiNbO₃ waveguides     

时差型卫星定位系统目标位置标校算法的误差分析

针对时差型卫星定位系统位置标校算法中标校源选择的问题,首先建立了基于单个标校源的标校方法的误差分析模型,分析了参数的系统性误差和随机测量误差对标校效果的影响;其次,定义了两类定位误差改善因子,用来定量描述标校算法对定位精度的改善能力,并可以通过理论计算评价标校源的标校效果,从而为标校源的选择提供了依据。最后,仿真分析验证了误差分析模型及定位误差改善因子的有效性。     

深空通信中结合位置与相位信息的调制方法

随着人类空间探测的距离越来越远, 传统的相移键控(Phase-Shift Keying, PSK)调制信息传输方式面临着发端功率受限、收端解调门限高的挑战.结合远距离光学通信中常用的位置调制, 提出了一种深空通信中基于位置信息的PSK调制方法, 并给出了收发机的实现框图.理论分析与仿真结果均表明, 该调制方法与传统PSK调制相比具有解调门限低的特点, 同等发射功率下, 可为深空通信带来更远的传输距离以及更好的传输质量.     

An analytic continuation method for the analysis and design ofdispersive materials

All materials, by nature, possess a frequency-dependent permittivity. This dispersion can be expressed in the form of the Kramers-Kronig relations by invoking the analytic consequences of causality in the upper half of the complex frequency plane. However, the Hilbert transform pair character of these relations makes them useful only when half of the answer is already known. In order to derive a more general form useful for both synthesis and analysis of arbitrary materials, it is necessary to analytically continue the permittivity function into the lower half plane. Requiring that the dielectric polarization be expressible in terms of equations of motion, in addition to obeying causality, conservation of energy and the second law of thermodynamics is sufficient to obtain the desired expression as a sum of special complex functions. In the appropriate limits, this sum reduces to the Debye relaxation and Lorentz resonance models of dielectrics, but it also contains phenomena not expressible in terms of those classical models. In particular, the classic problem of the existence of optical transparency in water is resolved     

Error analysis of the moment method

Because of the widespread use of the Method of Moments for simulation of radiation and scattering problems, analysis and control of solution error is a significant concern in computational electromagnetics. The physical problem to be solved, its mesh representation, and the numerical method all impact accuracy. Although empirical approaches such as benchmarking are used almost exclusively in practice for code validation and accuracy assessment, a number of significant theoretical results have been obtained in recent years, including proofs of convergence and solution-error estimates. This work reviews fundamental concepts such as types of error measures, properties of the problem and numerical method that affect error, the optimality principle, and basic approximation error estimates. Analyses are given for surface-current and scattering-amplitude errors for several scatterers, including the effects of edge and corner singularities and quadrature error. We also review results on ill-conditioning due to resonance effects and the convergence rates of iterative linear-system solutions.     

Error analysis in indirect rotor position sensing of switchedreluctance motors

The phase excitation pulses of a switched reluctance motor (SRM) drive need to be properly synchronized with the rotor position for optimum torque production. Accuracy of this position information determines the efficiency and smoothness of the drive operation. This paper presents a method of analyzing the errors inherent to indirect rotor position sensing schemes. The error analysis in this paper breaks down the position error to its fundamental components in the position sensing system. As an illustration, the method is applied to two different indirect position sensing schemes. The same basic approach can be applied to evaluate other SRM position sensing schemes. The results are helpful in comparing the various sensing schemes, as well as focusing improvement efforts on the appropriate segment of the system     

双目测量系统目标相对位置误差分析

目标特征点三维坐标的测量精度直接影响目标位姿的解算,准确确定影响目标位姿的误差因素,对各项误差进行合理分配及综合,是提高目标测量精度的关键。目前,像点提取精度、特征点匹配精度根据现有算法已达到瓶颈,而在摄像机内部结构及标定等方面提高测量精度还有较大的研究空间。通过建立成像点坐标测量方程,综合分析各误差因素对目标位置的影响。通过实验分析与仿真,摄像机内部结构误差及标定误差对成像点坐标的影响在一个像素内,当f=0.031 9 m,目标距离为20 m时,目标位置总体测量精度为0.029 4 m。对光学成像系统内部结构的设计及电子器件的选型具有较大参考价值。     

Error analysis of a statistical decision method

For the recognition of patterns as members of certain classes it is assumed that the probability distributions of certain characteristic features are known. For a decision based on the maximum likelihood criterion bounds on the statistical error are derived. In the case of normally distributed and statistically independent features these bounds are evaluated. Conditions are given under which the error tends to zero as the number of characteristic features goes to infinity.