基于扩展EL的大地测量报表系统     

陈正生  吕志平  李昌贵  王鹏 《四川测绘》2010,33(4):159-161

通过分析现有大地测量数据报表格式中存在的问题，以基于XML的大地测量数据接口文档为数据模型，建立了以Word文档为模板的EL引擎，使用户能够方便地对大地测量报表模板的样式和内容进行动态控制和修改，实现了数据库管理系统与报表系统、报表格式和数据内容的解耦，增加了报表的灵活性和扩展性。  相似文献   

流动卫星激光测距技术在中国的发展     

秦宽  魏二虎  严韦 《测绘科学》2007,32(2):169-171

SLR(卫星激光测距)技术是一项应用广泛的空间大地测量技术,本文在介绍其测距原理的基础上,通过与GPS、VLBI技术进行对比,分析了其实现手段和所能达到的精度;根据SLR应用现状提出了在国内建立SLR流动站的思路;并对SLR技术的未来发展作了展望。  相似文献   

基于网络资源的“大地测量学基础”教学创新模式探索     

李健  李保利  乔书波 《测绘工程》2009,18(1):77-80

针对“大地测量学基础”课程的特点和教学目标，对基于网络资源的教学创新模式进行探索和实践，有效地规范网络教学秩序，较好地保证网络教学效果，促进信息技术与教学活动的整合，并为个性化、研究式教学方法在网络教学领域内的具体实践提供环境依托。  相似文献   

国际南极大地参考框架的构建与进展   总被引：10，自引：2，他引：8  

鄂栋臣  张胜凯 《大地测量与地球动力学》2006,26(2):104-108

回顾了南极大地参考框架发展的历史,总结了由国际南极研究科学委员会(SCAR)组织的历次南极地区大地测量观测活动的成果,并结合2007~2008第四次国际极地年(IPY)对南极大地参考框架的前景进行了展望,其中重点介绍了我国对构建南极大地参考框架的贡献。  相似文献   

形变大地测量学的进展、问题与地震预报   总被引：12，自引：7，他引：5  

周硕愚  吴云  李正媛  杜瑞林 《大地测量与地球动力学》2004,24(4):95-101

简要概括了形变大地测量学的革命性进展，研讨了它的科学特色、功能和定义以及对地球科学和防灾减灾的推动。形变大地测量学有助于从根本上击破多年来制约地震预报的“瓶颈”，但也存在不少急待解决的问题。着重研讨了在21世纪前10年，形变大地测量学如何依托多年的学科积累并充分受益于人造卫星和数字化等新技术，开展创新性研究和试验以推进地震预报。为此，对当前的研究工作提出了12条科学技术途径。最后对学科名称提出了建议。  相似文献   

Seismic potential of Southern Italy   总被引：1，自引：2，他引：1  

S. Jenny  S. Goes  D. Giardini  H.-G. Kahle 《Tectonophysics》2006,415(1-4):81-101

To improve estimates of the long-term average seismic potential of the slowly straining South Central Mediterranean plate boundary zone, we integrate constraints on tectonic style and deformation rates from geodetic and geologic data with the traditional constraints from seismicity catalogs. We express seismic potential (long-term average earthquake recurrence rates as a function of magnitude) in the form of truncated Gutenberg–Richter distributions for seven seismotectonic source zones. Seismic coupling seems to be large or even complete in most zones. An exception is the southern Tyrrhenian thrust zone, where most of the African–European convergence is accommodated. Here aseismic deformation is estimated to range from at least 25% along the western part to almost 100% aseismic slip around the Aeolian Islands. Even so, seismic potential of this zone has previously been significantly underestimated, due to the low levels of recorded past seismicity. By contrast, the series of 19 M6–7 earthquakes that hit Calabria in the 18th and 19th century released tectonic strain rates accumulated over time spans up to several times the catalog duration, and seismic potential is revised downward. The southern Tyrrhenian thrust zone and the extensional Calabrian faults, as well as the northeastern Sicilian transtensional zone between them (which includes the Messina Straits, where a destructive M7 event occurred in 1908), all have a similar seismic potential with minimum recurrence times of M ≥ 6.5 of 150–220 years. This potential is lower than that of the Southern Apennines (M ≥ 6.5 recurring every 60 to 140 years), but higher than that of southeastern Sicily (minimum M ≥ 6.5 recurrence times of 400 years). The high seismicity levels recorded in southeastern Sicily indicate some clustering and are most compatible with a tectonic scenario where the Ionian deforms internally, and motions at the Calabrian Trench are small. The estimated seismic potential for the Calabrian Trench and Central and Western Sicily are the lowest (minimum M ≥ 6.5 recurrence times of 550–800 years). Most zones are probably capable of generating earthquakes up to magnitudes 7–7.5, with the exception of Central and Western Sicily where maximum events sizes most likely do not exceed 7.  相似文献   

Effect of common point selection on coordinate transformation parameter determination   总被引：2，自引：0，他引：2  

H. S. Kutoglu  P. Vaníček 《Studia Geophysica et Geodaetica》2006,50(4):525-536

The use of satellite positioning techniques commonly requires a transformation from a Conventional Terrestrial coordinate system to a Geodetic coordinate system, or vice versa. For such a transformation, the main problem is the determination of transformation parameters between these coordinate systems. The transformation parameters are estimated by a least-squares process using “common” points, i.e., those points whose coordinates are known in both systems. Therefore, the precision of so estimated transformation parameters is closely related to certain characteristics of the common points. In this contribution, we have formulated some theoretical relations between the transformation parameters and the number and the distribution of common points, and corroborated the theoretical results numerically, using a simulated geodetic network.  相似文献   

基于PCWin98经济网络分布式动力大地测量学数据库的设计与实现   总被引：1，自引：1，他引：0  

罗少聪 《地球物理学进展》2000,15(4):97-103

分析了动力大地测量学数据的结构和应用特点,结构现有网络和计算机软硬件状况,兼顾使用者的计算机水平和建库的人物力条件,得出了建立地测量学科数据库的思路和方案,建成基于Ｗｉｎ９８经济网络分布式动力大地测量学数据库。基于Ｗｉｎ９８经济网络、以资源共享方式集成的数据库系统开发环境有很大的在线数据存储能力、灵活分散式的数据库实现模式和调用功能。实现了以往大型计算机才能完成的系统。目前,系统平时能满足一般需要,必要时完成大型复杂任务。已拥有中国及其邻区原始气象数据、全球平均气压数据、超导观测数据、中国邻区重力场数据、地球自转及其有关数据、海潮模型、重力模型、软件等子库,容量达数十千兆,为科研提供快捷的数据服务。为目前普遍使用的区域网用户提供一种可行的科学数据库实现模式。  相似文献   

The International GPS Service tracking network: Enabling diverse studies and projects through international cooperation   总被引：2，自引：0，他引：2  

A.W. Moore  R.E. Neilan 《Journal of Geodynamics》2005,40(4-5):461

The International GPS Service (IGS), formulated beginning in 1989 and formalized in 1994, was founded on the collaborative operation of approximately 30 permanent GPS stations to benefit global geodynamics. The same cooperative principles, today applied to a network of over 300 stations, still serve to maximize global benefit without unnecessary duplication of investment in global infrastructure. The scope of applications of the dataset has grown to include atmospheric, oceanographic, subdaily, and low-earth orbiter activities through working groups and pilot projects fostered within the IGS in the now traditional IGS spirit of collaboration. These activities and the IGS infrastructure are viewed as critical elements to the Global Geodetic Observing System. This presentation will review the present nature of the IGS tracking network and its ability to support new applications.  相似文献   

Numerical simulations of a Mars geodesy network experiment: Effect of orbiter angular momentum desaturation on Mars' rotation estimation     

P. Rosenblatt  J.C. Marty  J.P. Barriot  V. Dehant 《Planetary and Space Science》2004,52(11):965-975

The scientific objectives of a geodetic experiment based on a network of landers, such as NEIGE (NEtlander Ionosphere and Geodesy Experiment) are to improve the current knowledge of Mars' interior and atmosphere dynamics. Such a network science experiment allows monitoring the motions of the Martian rotation axis with a precision of a few centimeters (or milli-arc-seconds (mas)) over annual and sub-annual periods. Thereto, besides radio tracking of a Mars orbiter from the Earth, radio Doppler shifts between this orbiter and several landers at the planet's surface will be performed. From the analysis of these radio Doppler data, it is possible to reconstruct the orbiter motion and Mars' orientation in space. The errors on the orbit determination (position and velocity of the orbiter) have an impact on the geodetic parameters determination from the Doppler shifts and must be removed from the signal in order to achieve a high enough accuracy. In this paper, we perform numerical simulations of the two Doppler signals involved in such an experiment to estimate the impact of the spacecraft angular momentum desaturations on the determination of Mars' orientation variations. The attitude control of the orbiter needs such desaturation maneuvers regularly repeated. They produce velocity variations that must be taken into account when determining the orbit. For our simulations, we use a priori models of the Martian rotation and introduce the spacecraft velocity variations induced by each desaturation event. By a least-squares adjustment of the simulated Doppler signals, we then estimate the orbiter velocity variations and the parameters of the Mars' rotation model. We show that these velocity variations are ill resolved when the spacecraft is not tracked, therefore requiring a near-continuous tracking from the Earth to accurately determine the orbit. In such conditions we show that only 15- of lander-orbiter tracking per week allows recovering Mars' orientation parameters with a precision of a few mas over a period of 1 Martian year.  相似文献