FY-2气象卫星在轨管理工程测控关键技术(上)

介绍了风云二号(FY—2)地球静止轨道自旋气象卫星工程测控的关键技术。分析了位置保持、姿态确定、星蚀和日凌的原理，给出了位置保持、姿态控制策略和地影、月影、日凌预报算法。并提出了一种检验定姿结果正确性的方法，提供了相应的工程计算参数。这些策略都已成功地用于FY—2卫星的在轨管理工程测控。     

影子工资理论的发展与应用

影子工资是为实现一定的经济发展目标而人为确定的,比名义工资或实际工资更能准确地反映劳动力资源的真实价值,并能促进其合理流动与利用的经济价格。它不仅能合理地反映劳动力价值,而且还能反映社会消耗、劳动力市场的供求关系和劳动力资源的稀缺或过剩程度,有利于资源的优化配置。影子工资理论的发展经历了线性规划对偶法、市场均衡价格理论及其拓展、按贸易货物口岸价调节的国际市场价格理论等阶段。国际通用的影子工资测算方法有UNIDO法、L-M法、S-V-T法和阿拉伯法,等等。     

面向北斗短报文的在轨卫星健康监控体系

针对我国在轨卫星数量迅猛增长、健康状态复杂各异、测控管理难度日趋增大的态势,提出了面向北斗短报文的在轨卫星健康监控体系。分析了北斗短报文的应用现状,构建了“用户→北斗卫星→在轨卫星”前反向数据流向。考虑到北斗短报文的容量限制,优化设计了测控数据传输格式和内容;针对北斗短报文单向传输特性,探讨了可靠通信技术;针对星座大规模安全传递分发数据需求,研究了通用掩码技术。以北斗三号系统为对象,仿真计算了在轨卫星前反向数据时间特性。结果表明:基于北斗短报文的在轨卫星健康监控技术,可以为提高在轨卫星科学使用和寿命的精细化管理提供参考。     

甲烷-空气的二次爆炸流场实验研究

为了揭示二次爆炸的产生机制及其影响因素,采用带导管的柱形泄爆装置对向空气中泄爆的过程进行了实验。实验获得了在不同泄爆条件下清晰的时序阴影照片和外流场测点的压力历程。根据实验结果分析了二次爆炸的产生条件,并详细讨论了二次爆炸影响因素在不同泄爆条件的变化,从而分析和解释了二次爆炸强度在相应泄爆条件下的变化规律。     

Effects of in-track maneuver on Sun illumination conditions of near-circular low Earth orbits

By developing approximate analytical models considering the J₂ perturbation, the effects of an in-track maneuver on the orbital Sun illumination conditions of near-circular low Earth orbits are analyzed. First, two approximate models for the variations in orbital sunshine angles are developed, one for variations at a given time and the other for variations at a given argument of latitude. Next, two approximate models for variations in orbital arc in Earth shadow are developed, one considers the small eccentricity and the other uses the zero eccentricity. Finally, the developed approximate models are applied to analyzing the Sun illumination conditions of a typical in-track maneuver mission on a near-circular low Earth orbit. From the results obtained, three major conclusions can be drawn. First, the variations in orbital sunshine angles at a given time may reach tens of degrees when the drifting time reaches hundreds of orbital periods, and the approximate model for that situation cannot effectively approach the numerical results. Second, the variations in orbital sunshine angles for any given argument of latitude are only a couple of degrees even when the drifting time reaches 500 orbital periods, and the approximation model developed can effectively approach the numerical results. Third, for variations in orbital arc in Earth shadow, the approximate model considering the small eccentricity has simple expressions and can effectively approach the numerical results; in contrast, the approximate model using the zero eccentricity has relatively worse precision.     

基于SVR及阴影信息的SAR目标方位角估计

目标成像方位估计是合成孔径雷达（synthetic aperture radar,SAR）自动目标识别中一个重要的预处理过程。提出一种基于支持向量回归机（support vector machine for regression,SVR）并结合SAR目标阴影信息的方位角估计方法。首先通过长直边拟合法与脊波变换法对目标图像进行方位的粗估计．再由SVR完成精确估计。利用“运动与静止目标的获取与识别”（moving and stationary target acquisition and recognition, MSTAR）项目组提供的实测数据所做实验表明,此方法可以有效估计SAR目标方位角,精度高、泛化能力强．特别是在水平成像方位附近利用了目标的阴影信息,明显提高了相应区间的方位角估计精度。     

Semi-analytical investigations of high area-to-mass ratio geosynchronous space debris including Earth’s shadowing effects

This paper investigates the long-term perturbations of the orbits of geosynchronous space debris influenced by direct radiation pressure including the Earth’s shadowing effects. For this purpose, we propose an extension of our homemade semi-analytical theory [Valk, S., Lemaître, A., Deleflie, F. Semi-analytical theory of mean orbital motion for geosynchronous space debris under gravitational influence. Adv. Space Res., submitted for publication], based on the method developed by Aksnes [Aksnes, K. Short-period and long-period perturbations of a spherical satellite due to direct solar radiation. Celest. Mech. Dyn. Astron. 13, 89–104, 1976] and generalized into a more convenient non-singular formalism. The perturbations accounting for the direct radiation pressure with the Earth’s shadow are computed on a revolution-by-revolution basis, retaining the original osculating Hamiltonian disturbing function. In this framework, we compute the non-singular mean longitude at shadow entry and shadow exit at every orbital revolution in opposition to classical approaches where the singular eccentric anomalies at shadow entry and shadow exit are computed. This new algorithm is developed using non-singular variables. Consequently, it is particularly suitable for both near-circular and near-equatorial orbits as well as orbits which transit periodically around null eccentricities and null inclinations.The algorithm is tested by means of numerical integrations of the equations, averaged over the short periods, including radiation pressure, J₂, the combined Moon and Sun third body attraction as well as the long-term effects of the 1:1 resonance occurring for geosynchronous objects. As an extension of [Valk, S., Lemaître, A., Anselmo, L. Analytical and semi-analytical investigations of geosynchronous space debris with high area-to-mass ratios influenced by solar radiation pressure. Adv. Space Res., doi:10.1016/j.asr.2007.10.025, 2007b], we especially apply our analysis to space debris with area-to-mass as high as 20 m²/kg. This paper provides numerical and semi-analytical investigations leading to a deep understanding of the long-term evolution of the semi-major axis. Finally, these semi-analytical investigations are compared with accurate numerical integrations of the osculating equations of motion over time scales as high as 25 years.     

空间交会对接中太阳光照窗口的研究

在空间交会对接过程中，光学测量装置对目标航天器的观测将直接受太阳光照反射强度的影响，空间交会对接必须在满足太阳光照条件的前提下进行，从正常交会对接和异常交会对接两个方面，详细分析了满足目标航天器光照条件的光照弧段和光照窗口问题，并且简要地讨论了地影区对光照弧段和光照窗口的影响，最后通过一个仿真算例，具体说明了光照条件及地影区对交会对接的约束。     

阴影遮挡对太阳电池阵发电能力影响的仿真分析

航天器太阳电池阵的在轨发电能力会由于舱体等对太阳光的遮挡而受到影响。文章通过建立太阳电池电路模型,利用Saber仿真平台进行仿真,得到太阳电池单串电路遮挡片数与功率输出的关系曲线,利用MatLab进行了基于每个单串电池电路的遮挡计算,最终计算得到自主飞行阶段的阴影遮挡造成的太阳电池阵功率损失率。比较新计算方法与传统计算方法的计算结果表明,新方法的计算精度更高,尤其是在被遮挡的电池片数量较少时,新方法的优势更加突出。     

Analysis of the current density characteristics in through-mask electrochemical micromachining (TMEMM) for fabrication of micro-hole arrays on invar alloy film

Invar alloy consisting of 64% iron and 36% nickel has been widely used for the production of shadow masks for organic light emitting diodes(OLEDs) because of its low thermal expansion coefficient(1.86 ? 10à6cm/°C).To fabricate micro-hole arrays on 30 lm invar alloy film,through-mask electrochemical micromachining(TMEMM) was developed and combined with a portion of the photolithography etching process.For precise hole shapes,patterned photoresist(PR) film was applied as an insulating mask.To investigate the relationship between the current density and the material removal rate,the principle of the electrochemical machining was studied with a focus on the equation.The finite element method(FEM) was used to verify the influence of each parameter on the current density on the invar alloy film surface.The parameters considered were the thickness of the PR mask,inter-electrode gap(IEG),and electrolyte concentration.Design of experiments(DOE) was used to figure out the contribution of each parameter.A simulation was conducted with varying parameters to figure out their relationships with the current density.Optimization was conducted to select the suitable conditions.An experiment was carried out to verify the simulation results.It was possible to fabricate micro-hole arrays on invar alloy film using TMEMM,which is a promising method that can be applied to fabrications of OLEDs shadow masks.