Future Commercial Directions in Environmental Remote Sensing from Space

Potential developments are considered for commercial applications of environmental remote sensing from space. The key areas affecting the possible growth of commercial markets that apply the sciences of meteorology, oceanography, and hydrology are discussed and projections made for 1985-2000. These areas include technology developments, markets, fiscal issues, political/legal/regulatory issues, and others. The growth will not be primarily limited by technology, but important uncertainties exist in the fiscal, political, and market development areas. With proper definition of government and commercial roles, both sectors can continue to maintain U. S. leadership in this area.     

How Operational Oceanography Can Benefit from Dynamic Topography Estimates as Derived from Altimetry and Improved Geoid

With a precise geoid, GOCE will allow an estimation of absolute dynamic topography from altimetry. The projected benefits to operational oceanography and its applications are analyzed herein. After a brief overview of operational oceanography, we explain how the new geoids will be used in the future to improve real time altimeter products and to better constrain modelling and data assimilation systems. A significant impact is expected both for mesoscale (e.g. better estimations and forecasts of currents for pollution monitoring, marine safety, offshore industry) and climate (better initialization of coupled ocean/atmosphere models) applications. This revised version was published online in August 2006 with corrections to the Cover Date.     

A state-of-the-art review in radar polarimetry and its applicationsin remote sensing

The authors assess the state of the art, focusing on their own contributions. Covered areas are the electromagnetic inverse problem in radar polarimetry, coherent polarization radar theory, partially coherent polarization radar theory, vector (polarization) inverse scattering approaches, the polarimetric matched filter approach, polarimetric Doppler radar applications in meteorology and oceanography, and image fidelity in microwave vector diffraction tomographic imaging     

VII: CLOSING SESSION: GOCE: ESA's First Earth Explorer Core Mission

This paper introduces the first ESA Core Earth Explorer mission, GOCE, in the context of ESA's Living Planet programme. GOCE will measure highly accurate, high spatial resolution differential accelerations in three dimensions along a well characterised orbit: the mission is planned for launch in early 2006. The mission objectives are to obtain gravity gradient data such that new global and regional models of the static Earth's gravity field and of the geoid can be deduced at length scales down to 100 km. These products will have broad application in the fields of geodesy, oceanography, solid-earth physics and glaciology. This revised version was published online in August 2006 with corrections to the Cover Date.     

Resolution Needed for an Adequate Determination of the Mean Ocean Circulation from Altimetry and an Improved Geoid

The sea surface topography observed by satellite altimetry is a combination of the geoid and of the ocean dynamic topography. Satellite altimetry has thus the potential to supply quasi-global maps of mean sea surface heights from which the mean geostrophic surface ocean currents can be derived, provided that the geoid is known with a sufficient absolute accuracy. At present, however, given the limited accuracy of the best available geoid, altimetric mean sea surface topographies have been derived only up to degree 15 or so, i.e. for wavelengths of approximately 2000 km and larger. CHAMP, GRACE, and the future GOCE missions are dedicated to the improvement of the Earth's gravity field from space. Several studies have recently investigated the impact of these improvements for oceanography, concluding to reductions of uncertainties on the oceanic flux estimates as large as a factor of 2 in the regions of intense an narrow currents. The aim of this paper is to focus on what are the typical horizontal scales of the mean dynamic topography of the ocean, and to compare their characteristics to the error estimates expected from altimetry and these future geoids. It gives also an illustration of the oceanic features that will be resolved by the combination of altimetry and the GRACE and GOCE geoids. It further reassesses the very demanding requirements in term of accuracy and resolution agreed in the design of these new gravity missions for ocean science applications. The present study relies on recent very high-resolution numerical Ocean General Circulation Model simulations. This revised version was published online in August 2006 with corrections to the Cover Date.     

Measuring the Distribution of Ocean Mass Using GRACE

The Gravity Recovery and Climate Experiment (GRACE), which was successfully launched March 17, 2002, has the potential to create a new paradigm in satellite oceanography with an impact perhaps as large as was observed with the arrival of precision satellite altimetry via TOPEX/Poseidon (T/P) in 1992. The simulations presented here suggest that GRACE will be able to monitor non-secular changes in ocean mass on a global basis with a spatial resolution of ≈500 km and an accuracy of ≈3 mm water equivalent. It should be possible to recover global mean ocean mass variations to an accuracy of ≈1 mm, possibly much better if the atmospheric pressure modeling errors can be reduced. We have not considered the possibly significant errors that may arise due to temporal aliasing and secular gravity variations. Secular signals from glacial isostatic adjustment and the melting of polar ice mass are expected to be quite large, and will complicate the recovery of secular ocean mass variations. Nevertheless, GRACE will provide unprecedented insight into the mass components of sea level change, especially when combined with coincident satellite altimeter measurements. Progress on these issues would provide new insight into the response of sea level to climate change. This revised version was published online in August 2006 with corrections to the Cover Date.     

III: OCEAN CIRCULATION: Global Ocean Data Assimilation and Geoid Measurements

Parts of geodesy and physical oceanography are about to mature into a single modeling problem involving the simultaneous estimation of the marine geoid and the general circulation. Both fields will benefit. To this end, we present an ocean state estimation (data assimilation) framework which is designed to obtain a dynamically consistent picture of the changing ocean circulation by combining global ocean data sets of arbitrary type with a general circulation model (GCM). The impact of geoid measurements on such estimates of the ocean circulation are numerous. For the mean circulation, a precise geoid describes the reference frame for dynamical signals in altimetric sea surface height observations. For the time-varying ocean signal, changing geoid information might be a valuable new information about correcting the changing flow field on time scales from a few month to a year, but the quantitative utility of such information has not yet been demonstrated. For a consistent estimate, some knowledge of the prior error covariances of all data fields is required. The final result must be consistent with prior error estimates for the data. State estimation is thus one of the few quantitative consistency checks for new geoid measurements anticipated from forthcoming space missions. Practical quantitative methods will yield a best possible estimate of the dynamical sea surface which, when combined with satellite altimetric surfaces, will produce a best-estimate marine geoid. The anticipated accuracy and precision of such estimates raises some novel modeling error issues which have not conventionally been of concern (the Boussinesq approximation, self-attraction and loading). Model skill at very high frequencies is a major concern because of the need to de-alias the data obtained by the inevitable oceanic temporal undersampling dictated by realistic satellite orbit configurations. This revised version was published online in August 2006 with corrections to the Cover Date.     

V: SEA LEVEL: Benefits of GRACE and GOCE to sea level studies

The recently published Third Assessment Reports of the Intergovernmental Panel on Climate Change have underlined the scientific interest in, and practical importance of past and potential future sea level changes. Space gravity missions will provide major benefits to the understanding of the past, and, thereby, in the prediction of future, sea level changes in many ways. The proposal for the GOCE mission described well the improvements to be expected from improved gravity field and geoid models in oceanography (for example, in the measurement of the time-averaged, or ‘steady state’, ocean surface circulation and better estimation of ocean transports), in geophysics (in the improvement of geodynamic models for vertical land movements), in geodesy (in positioning of tide gauge data into the same reference frame as altimeter data, and in improvement of altimeter satellite orbits), and possibly in glaciology (in improved knowledge of bedrock topography and ice sheet mass fluxes). GRACE will make many important steps towards these ‘steady state’ aims. However, its main purpose is the provision of oceanographic (and hydrological and meteorological) temporally-varying gravity information, and should in effect function as a global ‘bottom pressure recorder’, providing further insight into the 3-D temporal variation of the ocean circulation, and of the global water budget in general. This paper summaries several of these issues, pointing the way towards improved accuracy of prediction of future sea level change. This revised version was published online in August 2006 with corrections to the Cover Date.     

复合材料无损检测技术的现状与展望

回顾了复合材料无损检测技术的发展 ,从材料、结构和服役 3个方面介绍了复合材料无损检测技术的现状及今后的发展趋势     

浅谈高校街舞队的体育营销策略

目前许多高校都建立了自己的街舞代表队,为我国街舞运动的发展做出了贡献,但高校街舞队的经费问题一直制约着队伍的发展。针对这一问题,建立高校街舞队体育营销体系,并从中获得了成功,为我国这一新兴群众体育项目的发展奠定了坚实的基础。     

EB-PVD法制备微层材料的研究

简要介绍了用于电子束物理气相沉积的设备及其发展，阐述了利用该技术制备微层材料的优点，同时对制备工艺和相应的材料性能作了详细的介绍，并指出使用电子束物理气相沉积技术制备微层材料具有广阔的发展前景。     

数字化车间及航空智能制造实践

智能制造作为一种新的制造模式已经成为制造业未来的发展方向。世界各国纷纷采取措施,推进本国智能制造技术发展。在航空制造领域,智能制造也成为未来的发展趋势。在现有数字化车间基础上,提出了涵盖基础物理层、中间管理层及顶端智能管控层的飞机结构件智能数字化车间架构,并对智能工艺、智能装备、智能管控等飞机结构件智能制造关键技术进行了研究,以为智能制造在航空工业领域的应用提供参考。     

基于自动代码生成技术的永磁同步电机控制

为缩短电机控制系统软件开发周期,减少手写代码人力消耗,将自动代码生成技术应用于机载燃油泵用电机控制系统的软件开发中,介绍了自动代码生成技术的特点及开发流程,在MATLABSimulink环境下搭建了基于矢量控制算法的永磁同步电机系统控制模型,通过实验将模型自动生成为嵌入式代码,成功的实现了电机的闭环控制,极大地提高了开发效率,达到了预期成果。     

空间大型星载抛物面天线研究进展

抛物面天线作为星载天线的重要组成部分,在深空探测、移动通信、国防事业、气象监测等方面均具有广泛应用,近年来随着上述学科的快速发展,抛物面天线的研究也越来越受到人们的重视。针对空间大型星载抛物面天线的发展与需求,首先系统地概括了国外星载抛物球面天线的发展现状,综述了刚性、网状以及充气式星载抛物球面天线,对各类星载抛物球面天线的结构、性能进行了较为详细的描述和分析,对国内在该领域的部分研究成果进行了简述。然后梳理了星载抛物柱面天线的发展,对国内外具有代表性的抛物柱面天线进行了介绍,对抛物球面天线和抛物柱面天线进行了参数对比与分析。接下来对近年来针对星载抛物面天线的相关技术进行了介绍。最后对星载抛物面天线的发展趋势做了简要分析与预测。     

轻小型太阳能/氢能无人机发展综述

轻小型无人机（UAV）在军民领域都有着广泛的用途，电动无人机由于其振动低、无污染、无排放等优势，已经成为无人机领域的发展热点。为了提高轻小型电动无人机的航时，清洁、高能量密度的太阳能和氢能成为非常可行的技术途径之一。本文总结了轻小型太阳能、氢能无人机的发展历程；梳理了相关的关键技术，并对太阳能、氢能无人机的总体设计方法和能源动力系统的发展进行了较为深入的探讨；最后，展望了该类无人机的发展趋势，并对所面临的挑战进行了预测。     

捷联式重力测量技术研究进展

本文简要论述了动态重力测量的发展动态,接着以国防科技大学近年来在重力测量领域的研究为出发点,对国防科技大学在捷联式重力测量领域的研究现状进行了分析和总结。主要论述了捷联式重力测量的关键技术、研究历程、基本原理和典型试验结果,并对未来的发展方向进行了展望。     

超精密加工技术在新形势下面临的任务

国防武器装备系统的需求推动了超精密加工技术的发展,本文首先从描述当今先进武器系统装备的特点出发,介绍了超精密加工技术在其中的应用。并在此基础上提出了我国超精密加工技术的发展思路以及近期面临的重要研究课题。     

智能化航空飞行控制技术的发展

随着航空器飞行环境的日益复杂,对航空器的任务性能需求也不断提升。为了应对飞行安全压力增大、驾驶员操纵负荷增加等问题,从航空飞行控制所面临的问题着手,对人工智能、航空飞行控制的发展历程和后续发展趋势进行初步的探讨。首先,对国内外人工智能技术以及智能化航空飞行控制技术的发展进行简要介绍及分析;然后,结合技术发展趋势对未来智能化航空飞行控制技术的发展趋势进行初步分析;最后,提出了目前航空飞行控制技术智能化发展的初步思路,为后续该领域技术的发展提供参考。     

仿真系统在型号研制中的作用和地位

仿真技术的应用范围已从作战领域扩展到武器型号研制领域。阐述仿真、仿真模型和仿真系统的基本概念和特点，以及分布交互仿真和虚拟仿真与型号研制的关系。以战术导弹为例探讨了仿真系统在型号研制、试验、评估和降低成本中的重要作用。     

无人驾驶直升机的技术发展及其关键技术

介绍了无人驾驶直升机的系统组成和技术特点，重点讨论了当前的研究进展和控制技术的发展，分析了发展无人驾驶直升机的关键技术，并对未来无人驾驶直升机的发展方向提出了展望。