In situ and remote sensing of thermospheric winds during the energy budget campaign

This paper summarizes the dynamical information obtained in the lower thermosphere during the Energy Budget Campaign, by three experimental techniques: rocket-borne falling spheres instrumented with accelerometers and Tri-Methyl-Aluminium (TMA) trails, and from a ground-based Fabry-Perot interferometer. Winds of 200–400 m/sec, accelerated by the momentum and energy inputs from the magnetosphere, were observed during the ‘B’ and ‘A2’ salvos (15/16 Nov 1980 and 30 Nov/1 Dec resp.), with perturbations as low as 100 km altitude during the ‘B’ salvo. A global model has been used to simulate the wide-scale consequences of these disturbances, and to aid estimation of the integrated energy and momentum inputs.     

The ion energy and mass analyzer on board the ‘Intercosmos-Bulgaria-1300’ satellite

An original instrument for ion energy distribution measurement in ionospheric plasma above the F-layer was designed and launched on board the ‘INTERCOSMOS-BULGARIA-1300’ satellite. The instrument performs differential energy analysis of ion species within the two energy ranges of 1 – 27 eV/q and 0.2–8keV/q.     

The low energy gamma-ray experiments on GRO in perspective

The NASA Gamma-Ray Observatory, GRO, will carry two instruments for low energy gamma-ray astronomy. The ‘Oriented Scintillation Spectrometer Experiment - OSSE’ represents the latest step in the evolution of collimated detectors. A large detection area, simultaneous source and background observation and rigorous control over systematic errors yield significant improvements in sensitivity over earlier instruments. The ‘Imaging Compton Telescope - COMPTEL’ brings the proven concept of the Compton telescope to the state of the art level. Position sensitive scintillation detectors make it possible to generate sky images with a resolution of about 2° over a f.o.v. of about 1 sr. The complementary nature of these two experiments promises a first in-depth exploration of the sky in a wavelength range which covers the transition from the X-ray sky to the apparently unrelated high energy gamma-ray sky. Possible directions of further evolution of these experiments will be discussed.     

基于Volterra级数的功放行为建模与简化

Volterra级数行为模型因其高复杂度而只适用于弱非线性系统,对于具有强非线性和长记忆效应的功率放大器,Volterra级数模型将包含大量的待辨识参数.对射频功率放大器的行为建模进行了研究,提出了功率放大器Volterra级数行为模型的简化方法,通过引入邻对角核控制因子和动态偏离阶数控制因子,合理移除了对信号输出影响较少甚至无关的辨识参数,从而在保证模型准确度的前提下有效地降低了模型的复杂度和参数提取时间.采用了一个10 W的射频功率放大器实例用于模型提取和验证,模型与仿真实验的数据结果对比表明,简化的Volterra行为模型能够很好地描述功放的非线性特性及记忆效应,验证了简化行为模型的有效性和灵活性.     

Monitoring the changing aereal extent of irrigated lands of the gefara plain,libya

The inventory of large often non-homogeneous tracts of land by resource agencies has led to the development of estimation methods and sampling strategies that produce estimates of the aereal extent of various features from ‘limited’ observations of the universe of interest. Landsat data has furnished a tool that allows for potential improvement in estimates of resource parameters over extensive areas. This paper examines the methodology and results of a procedure which uses an economical sampling procedure allied with the large area covering qualities of the satellite imaging system to make improved estimates of irrigated land in a more timely, efficient and ‘accurate’ manner.     

How far is far enough? Requirements derivation for planetary mobility systems

The origination of duration and distance requirements on planetary mobility systems (generally, rovers) are reviewed in detail. It is found that a ‘clean’ flow down from scientific objectives to requirement to capability is rarely presented. Rather, the historical record shows that the capability of emerging designs has been adopted post-hoc as a requirement, simple comparative superiority to predecessor missions has been invoked in competitive situations, or the requirement has been driven by capability of other elements of a mission architecture, such as delivery precision or astronaut life support. These deviations from the idealized systems engineering process have nonetheless resulted in missions that have generally been considered highly successful.     

The location and intrinsic luminosity of the hidden nucleus of NGC 1068

Two key problems on the ‘hidden’ nucleus of NGC 1068 are discussed, based on the archival Hubble Space Telescope images. First, we discuss the accurate location of the nucleus. We have found that the most probable location is only ∼ 0.″1 (∼ 7 pc) south of the UV brightest cloud. Second, we consider the intrinsic luminosity of the hidden nucleus. We show that its lower limit is as large as ∼ 2 × 10⁴⁵ erg/sec, suggesting that the luminosity is almost at the Eddington limit.     

Dark Matter Particle Explorer:The First Chinese Cosmic Ray and Hard γ-ray Detector in Space

The Dark Matter Particle Explorer (DAMPE) mission is one of the five scientific space science missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Science (CAS) approved in 2011. The main scientific objective of DAMPE is to detect electrons and photons in the range of 5GeV-10TeV with unprecedented energy resolution (1.5% at 100GeV) in order to identify possible Dark Matter (DM) signatures. It will also measure the flux of nuclei up to above 500TeV with excellent energy resolution (40% at 800GeV), which will bring new insights to the origin and propagation high energy cosmic rays. With its excellent photon detection capability, the DAMPE mission is well placed for new discoveries in high energy-ray astronomy as well.      

Optimisation of X-ray proportional counters for Scanning Sky Monitor (SSM) on ASTROSAT

The Scanning Sky Monitor (SSM) on ASTROSAT is a position-sensitive gas-filled proportional counter with a wide field of view. The scientific objective of SSM is to scan the sky within few hours to detect and locate transient X-ray sources in the outburst phase. Once detected, this information will be provided for studies in all energy bands. The energy range of operation of SSM is 2–10 keV. The optimisation of the parameters of the proportional counter such as the cell size, the gas mixture and the gas pressure for the SSM are discussed here.     

Investigation of magnetospheric processes with the use of a source of strong magnetic field in the ionosphere

More than 20 years ago V.P. Shabansky suggested that the magnetic system installed aboard the satellite, could be used as a physical instrument for studying the processes which occur in the near Earth space. The corresponding space scales of an artificial “magnetosphere”—“magnisphere”—are 10 m in the experiment with relatively small magnets in the ionosphere and 100 m in the solar wind. The corresponding similarity criteria are estimated. The possible scheme of the experiment with a superconducting magnet (magnetic moment 10⁵ A · m²) installed aboard the satellite is considered. The experimental complex includes a number of systems for measuring the fluxes of charged particles in a wide energy range, DC electric and magnetic fields, the electromagnetic fields in different frequency bands (from X-rays to radio). The scientific objectives are discussed in detail.     

Solar and cosmic X- and gamma-ray studies with long duration balloon flights

The scientific goals of balloon-borne X and gamma ray transient studies are reviewed. Several scientific objectives are common to both solar and cosmic investigations, specifically: high time and energy resolution measurements of line and continuum emission, and log N-log S studies. A brief survey of six instruments is presented. It is shown that current proven detector and gondola technologies are sufficient to advance significantly our understanding of transient phenomena via these investigations within the decade and within the current and future constraints of proposed long duration (10–30 days) balloon facilities.     

地月第二拉格朗日点卫星激光测距技术研究

介绍了月球/中继星激光测距的科学意义、研究状况和发展趋势;研究了地月第二拉格朗日点(L2点)纯反射式激光测距技术和任务设计,主要包含单体大孔径激光角锥反射器的设计与研制,以及基于云南天文台1.2 m望远镜的月球/中继星激光测距系统研究。研究结果表明:采用单脉冲能量3 J和10 ns脉宽脉冲激光器,预期系统能接收到的单脉冲回波光电子数约为0.74,单光子测距精度优于1 m。     

Passive remote sensing of aerosols from space now and in the future

Aerosols modify scattered solar radiation leaving the atmosphere and this fact will be exploited to determine the aerosol optical depth. The interaction processes between solar radiation and aerosol particles are outlined. A quasi-linear relationship (‘conversion curves’) between the radiance at the satellite, L_sat, and the aerosol optical depth, a_Dλ, is found from both numerical and empirical studies. Because L_sat is not only controlled by a_Dλ, but also by a series of other atmospheric parameters (perturbing quantities), the concept of ‘favourable viewing conditions’ is presented, where the effects of the perturbing quantities are minimal. The paper ends with some lines of thought on a concept for a turbidity satellite.     

Analysis of the Bugatti data for turbulent parameters

The high frequency measurements of N₂ and Ar concentrations by rocket borne mass spectrometers in the region 95 to ∼ 120 km are analysed for turbulence coefficients. The data, measured every 2m, are averaged over 20 m, and spectrally analysed. The spectra in the lower altitude region (Z < 108 km) are representative of lower atmospheric turbulence wherein the spectrum displays the “inertial” behavior. Thus we may determine turbulent parameters such as: viscous dissipation (ϵ), Reynolds stress (<u‘w’>), density flux (<w‘n’), diffusivity (K_ϱ), the flux Richardson number, mean wind shear and an estimate of local temperature.Also determined at the upper region (108<z<120 km) is a non-“turbulent” noise-like fluctuation that diffusively transfers mass, but demonstrates random statistics. Density, spectral distributions, analytic processes and statistical characteristics of the two atmospheric mechanisms will be given.     

以载荷为中心的暗物质探测卫星机电热一体化设计

暗物质粒子探测卫星是中国第一颗空间高能探测卫星,用于实现5GeV~10TeV大动态范围高能宇宙线（电子、正电子、伽马射线等）能谱测量.卫星有效载荷包括BGO量能器、硅阵列探测器、塑闪阵列探测器和中子探测器,是目前中国发射的载荷比最大的卫星.本文介绍了卫星相关技术方案,包括技术指标、轨道方案、工作模式及系统组成等,突出了其以载荷为中心的机电热一体化设计特点.      

GPS/INU/DM组合定位导航技术在ITS中的应用

 介绍了智能交通系统(ITS,Intelligent Transport Systems)的基本思想,阐述了GPS/INU/DM(Global Positioning System/Inertial Navigation Unit/Digital Map)组合定位导航技术在ITS中的应用,以及提高组合定位导航精度及可靠性的几种技术措施.该组合定位导航是将卫星定位技术、惯性导航定位技术以及计算机技术融合在一起的新型技术,具有全方位、全天候、防遮挡的功能.ITS中利用组合导航技术可实现道路交通管理"自动化"、车辆行驶"智能化",具有良好的实用价值,应用前景广泛.