激光跟踪仪测角精度评定方法

本文以Leica AT901＿B激光跟踪仪为测试仪器,进行测角精度的评定研究。由于缺乏严密的角度检校标准,本文参考经纬仪／全站仪系统检校规范,提出以常规的角度检校模型为基础,采用全圆方向观测法获取数据,通过坐标反算观测值来计算系统轴系误差2C值和I角误差,并通过最小二乘平差原理解算系统水平角误差和垂直角误差。该方法基于严密的经纬仪／全站仪角度检校模型,真实地反映了激光跟踪仪的轴系误差和测角精度。通过数据的平差解算,求得AT901＿B的水平和垂直测角精度分别为0．54″和0．52″,由此评定出AT901＿B激光跟踪仪的实测精度符合其标称精度。     

3100型智能齿轮双面啮合综合测量仪

一、仪器特点310 0型智能齿轮双面啮合综合测量仪为机电一体化的新型自动化、智能化的齿轮测量仪器 ,具有体积小、重量轻、操作方便、稳定性好等特点。主要用于测量圆柱齿轮径向综合总偏差Fi″和一齿径向综合偏差 fi″以及径向跳动Fr″,自动判别并“挑出”存在齿面毛刺和划痕的齿牙。本仪器在测量中由微机显示屏和键盘以对话方式输入测量要求和参数 ,由微机控制进行自动测量与数据处理 ,显示屏显示测量结果与误差曲线 ,还可以由打印机输出检测报告。二、仪器的结构与工作原理仪器的结构参见图 1。 310 0型智能齿轮双面啮合综合测量仪的主机…     

光学分度头示值误差检修中的一些问题

一、示值误差的检定光学分度头是目前工厂计量室常用的测角仪器。其规格有刻度值为:2″、3″、6″,10″等不同型号。示值误差的检定有两种方法,对刻度值i=10″或低精度的分度头采用四方形铁(±5″)和测微表(0.001±0.5微米)组合检定;对刻度值为2″、3″、6″的分度头采用1″自准直仪和正多面棱体组合检定。     

红旗沟小流域治理效益卓越

1概述 红旗沟小流域位于内蒙古自治区乌拉特前旗东南部白彦花镇境内,属黄河一级支流（三湖河）的上游。总面积37．6km2,地理坐标为东经109°16′00″至109°19′49″,北纬40°37′38″至40°39′10″,海拔高程i021m-2035m之间,     

线阵CCD用于二维小角度测量的研究

介绍了线阵CCD器件用于二线小角度测量的研究,给出了一种线阵（二双坐标自准直仪及其测量原理、仪器硬件和软件设计。实验表明：所研制的CCD双坐标自准在仪量程为±5,分辨力优于0．2",测量精度优于1"。     

角度传感器校准及测量不确定度评定方法研究

文章设计了一种在多齿分度台上进行角度传感器的检定校准方案。与传统的分度头上校准相比较,本方法装夹方便,调整快捷,大大提高了工作效率和测量准确度,测回重复性由5″提高到1.5″,测量不确定度由15″提高到9″。     

二级角度块角度偏差测量结果不确定度评定

一、测量原理使用最大允许示值误差为±2″的测角仪,依据JJG70-2004《角度块》检定规程规定的方法对工作角为50°的二等角度块角度偏差进行连续测量,得到测量结果分别为-21″、-24″、-19″、-18″、-17″、-23″、-19″、-20″、-21″、-18″。取该组数据的平均值为输入测量的最佳估计值-20″,测量结果为49°59′40″。     

CCD激光自准直系统测光电经纬仪车载平台变形

车载平台变形是影响光电经纬仪跟踪精度的关键因素,提出了利用CCD激光自准直测量系统来测量车载平台变形的新方法。用CCD系统采集车载平台的变形视频信号,计算机对视频信号进行处理得到脱靶量数据,由此即可算出车载平台变形量。实验数据分析结果表明,车载平台变形量随着速度和加速度呈周期性变化,变形曲线的趋势与加速度曲线的趋势相同。当经纬仪以60°/s速度引导工作时,方位最大变形为12.57″,高低最大变形为5.98″。这种方法为进一步研究反馈补偿以提高经纬仪的跟踪精度提供了理论依据。     

磁光调制对准技术的研究

本文介绍利用法拉第效应进行磁光调制的原理、装置和实验结果。在一般条件下可达到灵敏度小于0.2″,平衡稳定度小于0.5″。     

用InGaN蓝光LED与YAG荧光粉制造自然白光LED

报导了用国内自行研制的InGaN/GaN蓝光发光二极管（LED）与钇铝石榴石（YAG）荧光粉结合而得的白光发光二极管（W－LED），在室温，正向电压3．5V，正向电流20mA时，W－LED轴向亮度为1cd,CIE色坐标为（0．31，0．38），接近纯白色（0．33，0．33）。     

High-accuracy gas analysis via isotope dilution mass spectrometry: carbon dioxide in air

An absolute method, based on isotope dilution mass spectrometry, is described for the determination of atmospheric concentrations of carbon dioxide (CO2) in dry air. In this study, the relative amounts of sample and spike gases are measured manometrically under temperature control before blending. The spike CO2 composition is approximately 0.1 atom % 13C while the oxygen isotopic composition is "normal". Exhaustive assessment of potential error sources leads to accountability of observed imprecision and determination of accuracy confidence intervals (CI). The imprecision interval (95% CI) about the mean is smaller than +/- 0.1% (+/- 0.4 mumol/mol) while the accuracy interval (95% CI) is +/- 0.15% (+/- 0.52 mumol/mol) for air having a CO2 concentration of about 350 mumol/mol. Calculated concentrations of CO2 are statistically indistinguishable from those generated by gravimetry, an independent method of analysis. In this study, the major contributors to uncertainty and imprecision are the predetermination of the gas volume ratio and the measurement of the isotopic composition of the blended CO2, respectively.     

A digital electronic instrument for production testing of condensers

Conclusion The analysis of the inaccuracies involved, given above, and experimentation on a breadboard model of the instrument justify the conclusion that, when high-stability condensers are used in the arms of the Wien bridge, rejection of condensers deviating from their nominal value can be carried out by means of this instrument with an accuracy of the order of 0.1%, and rejection relative to a standard of comparison with an accuracy of the order of 0.05% is possible. It should be noted that lack of constancy of the other components of the two Wien oscillator bridges is of no importance, because their change will not produce the ₁ inaccuracy, but only inaccuracies ₄ and ₅, which are very small. When ordinary condensers are used as standard capacities C_s, the instrument will guarantee a relative accuracy of at least 0.1% in routine acceptance tests, and even better accuracy in spot tests.Engineer Yu. L. Sokolov took part in the experimental work on this device and in the working out and adjustment of the breadboard model.     

A Universal Potentiometer for the Range from One Nanovolt to Ten Volts

Recent interest in accurate dc measurements down to nanovolt levels has prompted the development of a wide voltage range potentiometer of a new type with 7 dial resolution and extremely high accuracy. The potentiometer design is almost perfectly "neutral." All switch contacts and resistors of the main potentiometer operate at high voltage levels, and contribute thermal EMFs which are attenuated by a factor of ten thousand times (to less than 0.1 nanovolt levels) on the nanovolt range. The device serves as an "autocertified" voltage potentiometer standard. It is certified traceable to National Bureau of Standards units using previously published " ratiometric" techniques and is capable of direct reading accuracy without correction from 2 ppm on the 10-volt range to 10 ppm of setting ±1 nanovolt on the 0.001-volt range. The Thevenin equivalent source resistance of the instrument is approximately 2.5 ohms on the 0.001-volt range, reducing Johnson noise levels to less than 1 nanovolt with practical null detector smoothing times. The instrument is designed so that it can be used both as a potentiometer and as a 7-dial Kelvin-Varley divider. The control portion of the instrument is separately packaged and can convert dividers now in use to this new type of universal potentiometer standard. This paper includes a complete theoretical study of the design characteristics of this state of the art potentiometer, and an analysis of all sources of error in the completed instrument.     

数字化光电跟踪伺服系统定位极限环的抑制

数字光电跟踪系统定位时将产生自振荡,在相平面下可描述为极限环。自振荡对定位精度影响较大,因此必须对其进行抑制。针对实际的数字光电跟踪伺服系统,提出一种描述方法,即用等效间隙非线性来描述其定位时非线性特性,且该间隙主要由光电传感器的滞后效应和伺服系统的摩擦死区引起。理论分析表明,双极PWM功率放大器的零点振颤特性可以抑制伺服系统的定位极限环。实验也证明,通过软件补偿以及PWM驱动模式设计来改善光电跟踪系统定位精度是可行的,定位精度由1.77提高到了22.23,大大抑制了定位非线性特性。     

Broad-Band Calorimeter for Precision Measurement of Millimeter- and Submillimeter-Wave Power

A millimeter-wave dry calorimeter has been developed for power levels of 0.1 to 100 mW. The estimated instrument error for power levels of 10-100 mW is less than 0.3 percent. The required time for final reading is only about 40 s, which makes the instrument very useful for general laboratory power measurement. The VSWR is less than 1.15 over the whole waveguide band 60-90 GHz. The construction is simple compared to other designs with comparable accuracy.     

测角仪分度误差测量不确定度的评定

测角仪是角度计量常用的仪器。高准确度的测角仪一般作为角度计量标准器使用。由于没有更高准确度的计量标准进行测角仪的检定,根据圆分度闭合即各相邻间隔分度误差的总和为零原理,采用全组合比较或常角对称联系法测量测角仪的分度误差。最新修订的测角仪检定规程(JJG97-2001)规定了1″级测角仪在首次检定或要对度盘进行修正时采用常角排列互比对称联系法,后续检定时采用23面棱体排列互比法检定。本文分别对两方法测量不确定度进行了评定,评定结果其不确定度均优于0．1″。     

A Fast Response Low-Frequency Voltmeter

A sampling voltmeter implemented with a microprocessor has been developed to perform as a true rms voltmeter and waveform analyzer. The instrument measures to 0.1 percent accuracy the true rms voltage of approximately sinusoidal inputs at voltages from 2 mV to 10 V and frequencies from 0.1 to 120 Hz. The major feature of the instrument is fast response time, with a total autoranging, settling, and measurement time of two signal periods for frequencies below 10 Hz.     

High-Precision Digital Volt Ratiometer by a Method of Measuring Difference of Magnetic Field among Three Windings

The purpose of this work is to establish a highly accurate automatic ratio measuring instrument for dc voltage and resistance. In voltage and resistance ratio measurements, accuracy of 0.1 ppm has now become necessary due to recent developments in quantum metrology. To obtain the accuracy, we have just developed a technique to automatically compensate the measuring error caused by the deviation of electrical components, such as resistances used in the instrument. The instrument described incorporates this technique. With internal reference voltage and resistance, it can be a precision voltohmmeter and also, it can be standardized to an external standard with an accuracy of 0.1 ppm.     

3700-4200-MHz Computer-Operated Measurement System for Loss, Phase, Delay, and Reflection

A computer-operated transmission measurement set intended to support development work on microwave components for FM radio systems in the 3700-4200-MHz range is described. The instrument is capable of measuring the complete S-parameter set of the device under test, over a range from 20-dB gain to 70-dB loss. Accuracies of transmission parameters for small loss are ±0.002 dB, ±0.01°, and ±0.1 ns. The basic measurement technique is that of "IF substitution," combined with rapid cyclic comparison (30-Hz rate) of the parameters of the unknown with those of a stable microwave reference. The comparison feature eliminates errors from circuit drift, thus allowing attainment of the high accuracies sought. The test set design, the control of error sources, and the validation of accuracy are discussed.     

Microcomputer-Controlled Precision Pneumatic Pressure Generator

An increasing variety of avionics require precision pneumatic pressure stimuli during organization and intermediate maintenance. The accuracy and long-term stability requirements approach the best mercurial standards. Pressure stimuli must be coordinated and varied at precise rates that are beyond the frequency response of mercury columns and many electromechanical sensors. Test systems are frequently required to simultaneously monitor and evaluate unit under test (UUT) response and generate pneumatic stimuli. In addition, the environment is frequently hostile, maintainability is paramount, performance must always be known and warmup time must be nil. Comprehensive trade studies, tests, and analyses were performed. This initial work indicated a new pressure generator should be a "smart" instrument and should use a pressure sensor not a density sensor. Current field and production experience indicates performance objectives have been exceeded and this new type of precision pressure generator can be readily incorporated in a variety of test systems or be used "stand-alone". This paper discusses the design implementation, features, and characteristics of this microcomputer controlled precision pneumatic pressure generator-a new "smart" test instrument.