用于守时系统中的单片机输出监控器的研制

ＭＤ－１输出监控是一个Ｉｎｔｅｌ８０３１单片机系统，具有时间比对测量、标准时间频率信号隔离输出、监控报警等功能。与ＰＣ微机配合，可建立具有自动守时功能的标准时间工作站。文中介绍了该仪器的软件硬件设计。     

一种高精度时间同步器的研制与性能测试

针对移动通信网络基站间需要建立高精度时间同步的需求,研制了一种具有高精度时间同步功能和高精度频率输出的时间同步器,并设计了相应的性能测试方法。测试结果表明,在同等条件下,不同时间同步器输出的1PPS平均同步精度优于5ns／d,24h内输出的频率准确度优于10^-12／s,其他各项指标基本合格,符合设计要求。     

主钟的频率驾驭算法研究

各时间实验室产生的标准时间UTC(k)是UTC(协调世界时)在各时间实验室的物理实现.为了更好地驾驭主钟系统,使得主钟系统输出时间与标准时间UTC的偏差尽可能地小,且主钟系统输出的信号满足好的短、长期稳定度,因此提出了一种新的驾驭算法,并编制了相应的软件,自动定时计算给出相位微调仪的调整量,从而使频率驾驭后的主钟系统输出时间与标准时间UTC的偏差控制在较小的相位偏差范围内,并尽量不影响其稳定度.测试结果表明了新的主钟频率驾驭算法可以实现相位偏差保持在±15 ns之内,并且在保证不降低UTC(k)长期稳定度的前提下,可以提高它的短期稳定度.     

用于JATC远程时间比对的双频GPS接收机

中国科学院国家授时中心为“我国综合原子时（JATC）建立与保持的研究”项目研制的双频多通道GPS时间传递接收机NTSCGPS-2，不仅具有远程时间比对的功能，还增加了我国综合原子时需要的本地钟比对功能和精密定位功能。在不增加其它比对设备的情况下，满足JATC项目对远程时间比对的要求。NTSCGPS-2具有如下性能特点：（1）采用双频观测，可实测电离层时延；（2）远程（西安-上海、西安-澳门）时间比对精度达到2ns；（3）具有本地钟间的比对功能，在正常共视观测的同时，还可进行2个本地钟间的比对；（4）具有精密定位功能，相对定位精度为5cm。     

BPL长波授时信号质量的分析

利用CsSync1000型接收机的输出数据，分析了BPL信号在接收点的质量，还将该接收机的GRI与主钟（CSAO）1PPS比较，给出了接收时间内BPL发射系统时延变化范围。分析结果表明，BPL发播控制具有较好的短期和中期稳定性能。为进一步提高发播时间控制的稳定性，需要采用新的控制方法和控制设备。     

时间频率量的特征及其对时频系统建设的影响

分析了物理量测量中时间频率量的特点，主要有：时间的流逝性；其基准是自然基准；时间和频率既密切相关又有区别；时间频率具有最高的测量精细度(分辨率)与准确度；其计量标准可通过电磁波发播；其测量精确度与测量时间有关。另外，从基准、守时、授时、时间频率设备的研制、生产和队伍建设等方面阐发了这些特点对时间频率系统建设的影响。     

BPM短波授时信号模拟器的研制

介绍了BPM短波授时信号模拟器的主要功能和工作原理,阐述了该模拟器的系统组成、输入输出及软件流程。该模拟器以GPS信号作为时间源,以10 MHz的高稳定恒温晶振作为守时频率源,并在程序控制下产生载频与调制信号,放大输出6路BPM短波模拟信号。测试结果表明,该模拟器的功能与技术指标符合BPM短波授时信号的要求。     

上海天文台时频标准的传播

本回顾了上海天台标准时间频率的有源无线电发播简况（BPV、XSG），叙述了该台原子时频标准以TV、Loran-C和GMS为媒介的传播，在之前，并对时间频率标准的定义及演变作了简要介绍。     

用脉冲星钟作航天器时间标准

在介绍参考坐标系和时间标准的基础上,讨论了用脉冲星为航天器导航的时间标准问题。利用X射线脉冲星实现航天器自主导航,星载钟的任何误差都会直接影响航天器位置测量。脉冲星钟具有较高的长期频率稳定度,适合用作各类航天器的时间标准。重点讨论了时间标准误差对航天器定位的影响;给出了用脉冲星钟作航天器时间标准的物理实现方法。     

新的底片测量实时控制及数据采集系统

本文给出了用微机控制的３ＣＳ测微密度计的三路控制和三路数字采集的原理及功能，数据或图形输出方式，保证样品密度测量精度的方法。新的微机及接口，控制电路的引入，不仅增强了原３ＣＳ实时控制，资料处理、打印输出的功能，而且增加了实时图形显示和打印输出图形的功能。数据盘能适应现今通用的中小型计算机的要求，即增强了对被测对象的光学密度，位置测量和资料处理的能力。     

基于GPS实现测频等功能的虚拟仪器的研制

设计和研制了一种适用于大专院校示范教学实验的虚拟仪器。该虚拟仪器以GPS接收模块输出的1PPS(秒脉冲)信号为基准,测量无源石英晶体振荡器频率,同时利用GPS信号实现了仪器的时间同步与测距功能。从硬件和软件两方面描述了该虚拟仪器的构成及设计方法,主要介绍和讨论基于GPS和虚拟仪器技术实现多功能测量的途径。     

GPS同步恒星钟

主要叙述了利用ＧＰＳ定时接收机输出的时间信息和一系列电路完成平太阳时－恒星时转换的ＧＰＳ同步恒星钟的工作原理,以及“平化恒”时差改正的实现方法。     

MEASURING DOPPLER AND MAGNETIC FIELDS SIMULTANEOUSLY

A compact and inexpensive version of the magneto-optical filter, developed in Rome during the 1970s, has attained the capability to measure all the Stokes' parameters on the full solar disk. Without the help of moving parts, each Stokes' image is taken simultaneously with a companion Doppler image. The overall instrument is about 15 × 15 × 50 cm in size (telescope included). The working principle of the instrument is described first, then samples of its present applications are given. In this paper we address, for the first time, questions relating to the MOF lifetime and their implications on space applications.     

Laboratory verification of the Active Particle-induced X-ray Spectrometer(APXS) on the Chang'e-3 mission

In the Chang'e-3 mission, the Active Particle-induced X-ray Spectrometer(APXS) on the Yutu rover is used to analyze the chemical composition of lunar soil and rock samples. APXS data are only valid are only if the sensor head gets close to the target and integration time lasts long enough. Therefore, working distance and integration time are the dominant factors that affect APXS results. This study confirms the ability of APXS to detect elements and investigates the effects of distance and time on the measurements. We make use of a backup APXS instrument to determine the chemical composition of both powder and bulk samples under the conditions of different working distances and integration times. The results indicate that APXS can detect seven major elements, including Mg, Al, Si, K, Ca, Ti and Fe under the condition that the working distance is less than 30 mm and having an integration time of 30 min. The statistical deviation is smaller than 15%. This demonstrates the instrument's ability to detect major elements in the sample. Our measurements also indicate the increase of integration time could reduce the measurement error of peak area, which is useful for detecting the elements Mg, Al and Si. However, an increase in working distance can result in larger errors in measurement, which significantly affects the detection of the element Mg.     

B码设备中的GPS时间信号接口

ＰＯ９７型ＧＰＳ／Ｂ码解调器把ＧＰＳ技术融入Ｂ码设备中,用于自动定时定位和精密时间同步。该设备的ＧＰＳ时码接口解出ＧＰＳ时间信号,并同步所有的时标信号和时间码信号。主要介绍了该接口的硬件和软件的实现过程。     

An Observational Method to Prevent Cross-Talk and Calibrate Mof-Based Instruments

We present a method for calibrating every instrument working with magneto-optical filter (MOF) technology, in order to take into account the effect in the observations due to the aging of the vapour cells. The method allows the evaluation of some characteristics of the transmission profile by modelling the blue and/or the red line intensity images acquired with the MOF system. In particular, it reveals the presence of unwanted spurious transmissions and prevents cross-talk between the intensity and velocity fluctuations. The method also gives information about the position of the “working point” of the instrument, i.e. the average wavelength position of its transmission profile, which is necessary for estimating the right solar atmospheric layer observed by the MOF. This analysis is powerful and fast: applied before every observing campaign, it enables setting Q the most suitable value for the cell temperature, which is one of the parameters that controls the MOF transmission profile.     

The magneto-optical filter

In this paper we describe a filter which utilizes magneto-optical effects for velocity fields measurements. The working principle of the instrument is described and its transmission profiles are given. Velocitygrams are shown of the five minutes oscillations (FMO) and the results compared with the expected (theoretical) signal from the instrument. We found a V _rms of 400 m s^–1 for the FMO.     

A miniature laser anemometer for measurement of wind speed and dust suspension on Mars

Suspended dust is a dominant component of the Martian environment. It has a major influence on atmospheric circulation and it is deposited widely over the planetary surface causing a serious hazard to instrumentation. In order to study dust transport, quantification of the wind flow and dust concentration are vital. A simple laser-based anemometer system is presented that is able to measure suspended dust grain velocity and turbulence from a landed spacecraft. This system has advantages over other techniques of wind speed determination in being insensitive to contamination or atmospheric conditions such as temperature, pressure or composition. For the first time it would allow direct measurement of the suspended dust concentration on Mars. A prototype instrument has been constructed and successfully tested in a wind tunnel facility under simulated Martian conditions. The optics are simple in design, light weight and the instrument has low power consumption. It is also robust and the output signal is easily interpreted, producing only a small data volume. Future improvements will be discussed, specifically modification to measure wind direction, the possibility of obtaining information about dust grain size and the construction of a flight model.     

The miniaturized Möessbauer spectrometer MIMOS II for the Phobos-Grunt mission

Möessbauer spectroscopy is a powerful tool for the mineralogical analysis of Fe-bearing materials. The miniaturized Möessbauer spectrometer MIMOS II has already been working on the surface of Mars for 6 years as part of the NASA Mars Exploration Rovers mission. The improved version of the instrument is a component of the scientific payload of the Phobos-Grunt mission. The scientific objectives of the instrument are the following: to identify the iron-bearing phases, to determine the quantitative distribution of iron among these phases, and to determine the distribution of iron among its oxidation states.