干涉合成孔径雷达及其在火山研究中的应用(第二部分:阿拉斯加火山的InSAR成像)(英文)

干涉合成孔径雷达是一项能够对地表变形进行测量的遥感技术,在一个巨大区域内,它的变形测量精度可达亚厘米级,而其空间分辨率则在数十米以内。本文对我们应用InSAR技术对阿拉斯加火山进行研究的最新成果进行了总结,同时包括火山的喷发和非喷发活动。这些研究成果表明InSAR不仅能够增进我们对阿拉斯加火山活动的理解,而且还能够增强我们对未来火山喷发情况及其灾害的预测能力。     

海潮对高精度GPS网的影响初探

本文叙述了海洋负荷潮改正的基本原理，结合算例分析了海潮对GPS网的影响，结果显示：对于近海地区较短时段的GPS观测，考虑海潮负荷改正可以明显地提高解算精度，特别对改善高程方向的精度贡献明显。影响可达数厘米，这种影响的量级对水平方向不明显；对于远离海洋地区，海潮负荷改正的影响已不明显，可以不与考虑。     

Letters from Carlos Ibáñez e Ibáñez de Ibero to Aimé Laussedat: new sources for the history of nineteenth century geodesy

Recently found letters written by Carlos Ibáñez e Ibáñez de Ibero (1825–1891), first president of the International Geodetic Association, to geodesist–photogrammetrist Aimé Laussedat (1819–1907) are discussed. The contents of these epistolary conversations reflect their personal preoccupation with solving the geodetic problems of the time (1857–1889) and their desire to develop and propagate geodetic knowledge across all international boundaries.     

卡尔曼滤波在VLBI数据处理中的应用

本文探讨卡尔曼滤波技术用于VLBI天体测量和大地测量数据处理的原理和方法;并深入地对Herring等提出的软件系统（SOLVK）进行详细研究,提出一些具体的办法以便应用．然后用1993—1994年的VLBI观测资料,精确计算了几种天文学和地球动力学参数作为例证．     

四维整体大地测量的有限单元法

本文以有限单元法为基础，将四维整体大地测量模型与固体力学方程求解构造应力场结合起来，在四维整体大地测量方程中加入了由地壳构造运动产生的地面点重力变化的观测方程，其中包含测点的位移参数，边界结点上待求以数利用有限单元法在四维整体大地测量平差过程中推估，采用统一的插值函数。     

大地参考系评论:过去、现在和未来

本文对不同时期所建立的大地参考系进行了分析和比较,并预测了大地参考系的未来和发展以及如何满足许多有关学科在发展中提出的要求。对于不同的大地参考系之间的转换,本文就各种相似变换模型、多项式和逐次回归方程等模型及其精度进行了评述。     

Geodetic control on recent tectonic movements in the central Mediterranean area

During the Neogene and Quaternary, the western Mediterranean geodynamics was apparently dominated by the nearly eastward migration of the Apenninic arc and the associated opening (spreading) of the back-arc basin (Tyrrhenian Sea). However, during the last 5 My, the collision of the arc with the Apulian platform led to a dramatic change in the tectonic setting of the area. As geological processes require a long period of time to register the displacements of the different blocks, it is indispensable to take into account the present-day motion given by space geodesy data analysis in order to better constrain the geological models.Geodetic motions were derived from Global Positioning System (GPS), Satellite Laser Ranging (SLR) and Very Long Baseline Interferometry (VLBI) observations collected from different networks. All the geodetic solutions have been computed and combined at the Centre of Space Geodesy (CGS), at Matera, Italy.The geodetic results show a NNE motion of the Adriatic plate with a small component of counter-clockwise rotation, in good agreement with the geological and geophysical observations.In the southern Tyrrhenian area, the lengthening of the Matera–Cagliari baseline should imply that convergence cannot be considered as the driving mechanism for the Apenninic subduction process. The estimated motion of Noto is in quite good agreement with the estimated motion of the African plate.     

Short-arc analysis of intersatellite tracking data in a gravity mapping mission

 A technique for the analysis of low–low intersatellite range-rate data in a gravity mapping mission is explored. The technique is based on standard tracking data analysis for orbit determination but uses a spherical coordinate representation of the 12 epoch state parameters describing the baseline between the two satellites. This representation of the state parameters is exploited to allow the intersatellite range-rate analysis to benefit from information provided by other tracking data types without large simultaneous multiple-data-type solutions. The technique appears especially valuable for estimating gravity from short arcs (e.g. less than 15 minutes) of data. Gravity recovery simulations which use short arcs are compared with those using arcs a day in length. For a high-inclination orbit, the short-arc analysis recovers low-order gravity coefficients remarkably well, although higher-order terms, especially sectorial terms, are less accurate. Simulations suggest that either long or short arcs of the Gravity Recovery and Climate Experiment (GRACE) data are likely to improve parts of the geopotential spectrum by orders of magnitude. Received: 26 June 2001 / Accepted: 21 January 2002