瞬时GPS姿态确定

本文介绍了瞬时GPS姿态确定方法,即只用单时刻测量值解GPS积分多普勒波长的模糊度。以前解相位模糊所用的大部分技术需要作某种形式的依赖GPS卫星和/或用户运动的时间历程处理,为消除不合理解提供足够的几何变化。本文介绍的算法假定使用两副以上天线(全部姿态确定需用三副以上天线),并从四颗以上卫星由一或两个GPS L波段载波测得积分多普勒测量值。利用专门的双差分处理得到测量误差不相关的观测量,用于计算天线相对位置及两个以上姿态欧拉角。针对利用4颗以上卫星及2副以上天线及一或两个GPS L波段载波频率(包括86cm宽巷道测量值),开发和演示了GPS姿态确定中快速解双差分载波相位模糊的算法。为希望瞬时GPS测姿的用户找出了实际设计极限。姿态快速确定中的重要因素之一是用户接收机跟踪的卫星数目,GPS金星座对此有很大好处。     

利用GPS进行精密轨道确定

全球定位系统(GPS)完全布满卫星后,将成为近地卫星的精密轨道确定(POD)强有力的工具。该系统具有连续跟踪覆盖能力,不仅可实现传统的动力学精密轨道确定方法,而且还可进行运动学轨道确定。来自至少四个GPS卫星的伪距测量值,通过载波相位测量值的平滑,可测定天线相位中心的地心位置和用户卫星的时钟修正值,因而后一技术不需要用户卫星受力的动力学模型。运动学法对测量模型的影响非常敏感,如GPS星历误差(给定的或求解的)、信号的多径、接收机噪声等等;然而,动力学方法又受参数误差和/或力模型不完善的影响。为此研究出一种利用过程噪声补偿对运动学和动力学算法进行加权的混合方案。本课题的中心点是利用仿真辅以协方差分析,研究这几种定轨方法。建立了几种动力学和测量误差模型,这些模型造成的轨道不确定性与处理实际GPS数据而估计的星历误差大致相当。协方差分析经调整能反映这些误差,能看出各种滤波技术的特性。     

用声表面波传感器进行压力和温度测量

本文介绍两种不同的声表面波传感器,即弱压压力传感器和声表面波温度传感器。压力传感器制作在一薄的石英晶片上,使两束表面弹性波在同一方向但在两个不同的侧向位置上传播。加在下表面上的压力的变化引起强烈的弯曲,从而改变两波的波速。采用差动检测法能够测出波速的变化(或者相应振荡器的频率偏移),同时也能够人大地消除因温度波动所引起的假速度(或频率)的变化。通过计算应变分布和相应频率漂移来得出石英薄片上声表面波延迟线具有最大压力灵敏度,而温度影响最小的两位置。把Y切割的理论结果与在105MHz取得的测帚结果进行了比较, 用具有LST和JCL晶向的石英片制作的温度传感器已在灵敏度(28ppm/K)、线性、响应时间(0.1S)和分辨力(50μK)方面进行了测试。将用表面波温度传感器取得的温度测量结果与用体波温度传感器(LC切)所测得的结果进行比较,提出一种采用声表面波温度探头的新型石英温度计。     

Ray Structure of the Coronal Streamer Belt and Its Manifestation as Sharp Large Peaks of Solar Wind Plasma Density at the Earth''''s Orbit

The white-light corona calibrated data with processing level L1 from the LASCO-C2/SOHO instrument, and data from the Wind spacecraft with one-hour and one-minute time resolution on quasi-stationary slow (v between 300-450 km/s at the Earth's orbit) the Solar Wind (SW) parameters in the absence of sporadic SW streams are examined. Within distances from the Sun's center less than R in the range of 20-30 Rs, (Rs, the solar radius), slow wind is known as the streamer belt, and at larger distances it is called the He-liospheric Plasma Sheet (HPS). It is shown that the streamer belt comprises a sequence of pairs of rays. In general, ray brightnesses in each pair can differ, and the magnetic field is oppositely directed in them. The neutral line of the radial magnetic field of the Sun runs along the belt between the rays of each of the pairs. The area in which the streamer belt intersects the ecliptic plane and which lies at the central meridian, will be recorded at the earth's orbit with a time delay of 5-6 days, in the form of one or several peaks with Nmax> 10cm-3. Furthermore, the simplest density profile of the portion of the HCS has the form of two peaks of a different or identical amplitude . The such a profile is observed in cases where the angle of intersection of the streamer belt with the ecliptic plane near the Sun is sufficiently large, i.e. close to 90°. The two-ray structure of the cross-section of the streamer-belt moves from the Sun to the Earth, it retains not only the angular size of the peaks but also the relative density variations, and the position of the neutral line (sector boundary) in between. At the Earth's orbit the ray structure of the streamer belt provides the source for sharp (i.e. with steep fronts of a duration of a few minutes or shorter) solar wind plasma density peaks (of a duration of several hours) with maximum values Nmax> 10cm-3.     

动态信号实时采集及处理的图形菜单式软件包

在振动信号的处理理论上提出一些新的方法和处理技巧，使在微机上快速、有效地实现成为可能。应用目前最有效的Ｃ语言及其编译系统ＢｏｒｌａｎｄＣ＋＋３．１，用面向对象的设计思想（ＯＯＰ技术）实现了从振动动态信号的数据采集、处理分析及结果图像显示输出等的完整过程，并在菜单设计技术、动态内存分配、热键过滤技术、系统自识别技术及二、三维图像绘制、输出等方面，取得了一定的突破和创新，使整个软件的功能得以实现，并具有操作简便，容错性好，提示信息丰富，数据交换兼容性好等特点。     

六一八所通过质量体系认证审核

1996年12月16日至19日,国家新时代认证中心按照GJB/Z9001-96、GB/T 19001-1994(等同于 idt ISO 9001:1994)的要求,对航空工业总公司六一八所质量保证体系进行了全面检查。 其检查结果表明,六一八所质量体系军品飞行控制系统和惯性导航系统的设计、开发、生产和服务符合GJB/I 9001-     

金权电传飞行控制系统数字计算机设计指南

本文介绍设计顾虑是:1)、“要求多少个通道”?2).“要求多大的复盖率”?3)、“表决系统的内检设备(BITE)的作用是什么”?文章陈述一组假定的基准,为六个不同的多计算机系统研制分析模型;并分析这些模型和给出图示结果,这些结果可由不同与被选择的基准值的参邮给予解释。文章介绍有关上面三个设计顾虑问题的专用设计准则。     

最小生理噪声进场航迹飞行管理方法

 微波着陆系统MLS的最优航迹计算以减小居民最敏感的生理噪声为基本优化性能准则,用感觉噪声级Sone为单位。计算了考虑了噪声传播时温度、风梯度、沿进场航迹附近区域生活居民区分布位置及密度等影响。通过对杜塞尔道夫-罗奥申航空港计算结果证实,使航空港附近居民的平均有效感觉生理噪声级(Sone)较原有Jeppesen标准方式降低了20％以上。     

Blood volume regulating hormones, fluid and electrolyte modifications during 21 and 198-day space flights (Altair-MIR 1993)

During the Altair MIR' 93 mission we studied several parameters involved in blood volume regulation. The experiment was done on two cosmonauts before (B-60, B-30), during (D6, D12, D18 for French and D7, D12, D17 for Russian) and after the flight (R+1, R+3 and R+7). Space flight durations were different for two cosmonauts: for the Russian the flight duration was 198 days and for the French 21 days. On board the MIR station only urinary (volume and electrolytes, atrial natriuretic peptide (ANP), cyclic guanosine monophosphate (cGMP) and catecholamines) and salivary (cGMP and cortisol) samples were collected, centrifuged and stored in freezer. Lithium was used as a tracer to know exactly the 24 h urine output (CNES urine collection Kit). Before and after flight, blood was drawn with an epicite needle and vacutainer system for hormonal assays (renin, antidiuretic hormone, cGMP, ANP and aldosterone) in two positions: after 30 min rest in upright seated position and after 90 min of supine position. Salivary samples were collected simultaneously. During flight a decrease of diuresis and ANP and an increase of osmolality were found. No modifications of hematocrit, but an increase of salivary cGMP and cortisol were also observed. The decrease of urinary ANP is in favor of hypovolemia as described in previous flights. The postflight examinations revealed changes in fluid-electrolyte metabolism which indicate a hypohydration status and a stimulation of hormonal system responsible for water and electrolyte retention in order to readapt to the normal gravity.     

Identification of morphological biosignatures in Martian analogue field specimens using in situ planetary instrumentation

We have investigated how morphological biosignatures (i.e., features related to life) might be identified with an array of viable instruments within the framework of robotic planetary surface operations at Mars. This is the first time such an integrated lab-based study has been conducted that incorporates space-qualified instrumentation designed for combined in situ imaging, analysis, and geotechnics (sampling). Specimens were selected on the basis of feature morphology, scale, and analogy to Mars rocks. Two types of morphological criteria were considered: potential signatures of extinct life (fossilized microbial filaments) and of extant life (crypto-chasmoendolithic microorganisms). The materials originated from a variety of topical martian analogue localities on Earth, including impact craters, high-latitude deserts, and hydrothermal deposits. Our in situ payload included a stereo camera, microscope, M?ssbauer spectrometer, and sampling device (all space-qualified units from Beagle 2), and an array of commercial instruments, including a multi-spectral imager, an X-ray spectrometer (calibrated to the Beagle 2 instrument), a micro-Raman spectrometer, and a bespoke (custom-designed) X-ray diffractometer. All experiments were conducted within the engineering constraints of in situ operations to generate realistic data and address the practical challenges of measurement. Our results demonstrate the importance of an integrated approach for this type of work. Each technique made a proportionate contribution to the overall effectiveness of our "pseudopayload" for biogenic assessment of samples yet highlighted a number of limitations of current space instrument technology for in situ astrobiology.