F-P滤波器和SOA在全光帧时钟提取中的分析和试验

F—P腔作为光滤波器用．具有稳定性高．通带窄的优点。采用低精细度的法布里-珀罗滤波器（F—P）直接提出帧时钟,保证时钟的快速建立和快速消失。利用半导体光放大器（SOA）的自增益调制效应（SGM）对F-P提取的帧时钟进行整形,降低帧时钟的幅度噪声。并推导了F—P的精细度Q和SOA的自增益调制效应对帧时钟建立时间、消失时间的影响。通过理论分析表明,利用SOA的SGM效应可以降低帧时钟的幅度噪声并加快帧时钟建立速度。实验中,用上述方案对10．075GHz的帧信号进行了全光帧时钟提取．得到了建立时间为8个信号周期．消失时间为22个信号周期抖动为2.35ps的帧时钟信号.     

An investigation of the solar cycle impact on the lower thermosphere O(S) nightglow emission as observed by WINDII/UARS

The yearly variation of the integrated emission rate of the O(¹S) nightglow in the lower thermosphere is studied and the solar cycle impact is examined from the observations of the Wind Imaging Interferometer (WINDII) operated on the Upper Atmosphere Research Satellite (UARS). More than 300,000 volume emission rate profiles of the O(¹S) nightglow observed by WINDII for 40°S–40°N latitudes during November 1991–August 1997 over half of a solar cycle are utilized. These profiles are vertically integrated for the altitude range of 80–100 km and the equivalent column integrated emission rates are then zonally averaged for bins with 10° latitude and 3 month intervals. It is found that for each latitude the O(¹S) nightglow emission rate appears to increase with increasing solar F10.7 cm flux, following a linear relationship. This characterizes the solar cycle impact on the O(¹S) nightglow, while the solar influence is modulated by a seasonal variation. Based on these variations, an empirical formula is derived for predicting the three-month averages of the O(¹S) nightglow integrated emission rate. The standard error of the estimated values from the formula is smaller than 30 Rayleigh.     

国防原子时测试系统的设计与实现

随着现代武器系统的日趋高速化、自动化和智能化,时间频率在高技术战争中的地位越来越突出,国防原子时系统的运行研究,将对我国独立自主的时间标准系统的建立提供有利的技术支持。本文较详尽地阐述了国防原子时测试系统的组成,并介绍了系统中比对测试软件、环境监测系统的设计以及相关数据库的搭建。     

磁选态铯原子钟弱信号直接采样方法研究

磁选态铯原子钟的输出频率与铯束管输出的弱电流信号有关，影响其频率稳定度。为了提高其频率稳定度技术指标，在对磁选态铯原子钟主伺服电路弱信号压频转换（V-F）和模/数 (A/D)直接采样对比的基础上，设计了基于DSP28335芯片的A/D直接采样电路，利用CAN总线通信技术与主控CPU板进行通信，实现整钟闭环锁定的方案。通过试验与被测磁选态铯原子钟现有压频转换法进行对比，结果表明，所设计的A/D直接采样法较压频转换法减小了磁选态铯原子钟相对频率偏差范围，改善了短期频率稳定度，具有实用价值。     

原子层沉积纳米钝化层薄膜厚度测量技术研究

原子层沉积无机纳米薄膜技术广泛应用于军民领域。本文通过在原子层沉积系统加装原位石英晶体微天平测量系统，通过原位石英晶体微天平研究原子层沉积无机薄膜生长过程并进行薄膜厚度的在线测量。通过研究原子层沉积反应条件，实现原子层沉积无机薄膜厚度的石英晶体微天平在线测量结果替代薄膜厚度线下光学测量结果，解决各类复杂腔体内壁原子层沉积薄膜厚度无法精确测量的问题。     

A new stochastic model considering satellite clock interpolation errors in precise point positioning

Precise clock products are typically interpolated based on the sampling interval of the observational data when they are used for in precise point positioning. However, due to the occurrence of white noise in atomic clocks, a residual component of such noise will inevitable reside within the observations when clock errors are interpolated, and such noise will affect the resolution of the positioning results. In this paper, which is based on a twenty-one-week analysis of the atomic clock noise characteristics of numerous satellites, a new stochastic observation model that considers satellite clock interpolation errors is proposed. First, the systematic error of each satellite in the IGR clock product was extracted using a wavelet de-noising method to obtain the empirical characteristics of atomic clock noise within each clock product. Then, based on those empirical characteristics, a stochastic observation model was structured that considered the satellite clock interpolation errors. Subsequently, the IGR and IGS clock products at different time intervals were used for experimental validation. A verification using 179 stations worldwide from the IGS showed that, compared with the conventional model, the convergence times using the stochastic model proposed in this study were respectively shortened by 4.8% and 4.0% when the IGR and IGS 300-s-interval clock products were used and by 19.1% and 19.4% when the 900-s-interval clock products were used. Furthermore, the disturbances during the initial phase of the calculation were also effectively improved.     

冗余箭载计算机余度管理

针对三模冗余箭载计算机，研究了取消硬件表决器单点情况下的CPU模块的冗余配置方法，引入了箭机关键参数自检测信息参与通道表决；对互反馈独立时钟进行了三取二表决，以生成时钟同步信号，进而将信号作为余度飞行控制软件的毫秒中断；采用多数表决和中值表决对输入输出的数字量、开关量、模拟量进行了监控与表决。功能试验结果表明，该余度管理方法能够有效应对典型的失效模式。最后，对下一步的通道隔离以及软硬件异构优化设计技术进行了展望。     

基于粒子群优化核极限学习机的北斗超快速钟差预报

针对卫星钟差序列中非线性特性较为复杂和超快速钟差预报精度较低的问题，将核极限学习机算法引入到北斗超快速钟差预报中。首先，将极限学习机进行优化，引入粒子群优化算法来选择核极限学习机所需的核参数和正则化参数；然后，将优化后的方法应用到超快速钟差预报中，并给出了利用该方法进行超快速钟差预报的步骤；最后，在分析iGMAS提供的实测北斗超快速钟差数据的基础上，选用单天和多天数据进行短期预报。结果表明：在短期预报6h范围内，利用本文提供的优化方法解算得到的超快速钟差预报精度明显优于二次多项式模型和周期项模型，并且采用此方法得到的超快速钟差预报产品与iGMAS提供的超快速钟差预报产品(ISU-P)相比，GEO、IGSO和MEO卫星的预报精度分别提升了50.51%、46.98%、40.67%，其与最终精密钟差的符合程度显著 增强 。     

The OIV 1407.3 Å /1401.1 Å emission-line ratio in a plasma

Line ratio of O IV 1407.3 Å/1401.1 Å is calculated using mostly our own atomic and collisional data.