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1.
《Journal of Geodynamics》2006,41(4-5):414-431
Towards the end of the 19th century, geodetic observation techniques allowed it to create geodetic networks of continental size. The insight that big networks can only be set up through international collaboration led to the establishment of an international collaboration called “Central European Arc Measurement”, the predecessor of the International Association of Geodesy (IAG), in 1864. The scope of IAG activities was extended already in the 19th century to include gravity.At the same time, astrometric observations could be made with an accuracy of a few tenths of an arcsecond. The accuracy stayed roughly on this level, till the space age opened the door for milliarcsecond (mas) astrometry. Astrometric observations allowed it at the end of the 19th century to prove the existence of polar motion. The insight that polar motion is almost unpredictable led to the establishment of the International Latitude Service (ILS) in 1899.The IAG and the ILS were the tools (a) to establish and maintain the terrestrial and the celestial reference systems, including the transformation parameters between the two systems, and (b) to determine the Earth's gravity field.Satellite-geodetic techniques and astrometric radio-interferometric techniques revolutionized geodesy in the second half of the 20th century. Satellite Laser Ranging (SLR) and methods based on the interferometric exploitation of microwave signals (stemming from Quasars and/or from satellites) allow it to realize the celestial reference frame with (sub-)mas accuracy, the global terrestrial reference frame with (sub-)cm accuracy, and to monitor the transformation between the systems with a high time resolution and (sub-)mas accuracy. This development led to the replacement of the ILS through the IERS, the International Earth Rotation Service in 1989.In the pre-space era, the Earth's gravity field could “only” be established by terrestrial methods. The determination of the Earth's gravitational field was revolutionized twice in the space era, first by observing geodetic satellites with optical, Laser, and Doppler techniques, secondly by implementing a continuous tracking with spaceborne GPS receivers in connection with satellite gradiometry. The sequence of the satellite gravity missions CHAMP, GRACE, and GOCE allow it to name the first decade of the 21st century the “decade of gravity field determination”.The techniques to establish and monitor the geometric and gravimetric reference frames are about to reach a mature state and will be the prevailing geodetic tools of the following decades. It is our duty to work in the spirit of our forefathers by creating similarly stable organizations within IAG with the declared goal to produce the geometric and gravimetric reference frames (including their time evolution) with the best available techniques and to make accurate and consistent products available to wider Earth sciences community as a basis for meaningful research in global change. IGGOS, the Integrated Global Geodetic Observing System, is IAG's attempt to achieve these goals. It is based on the well-functioning and well-established network of IAG services. 相似文献
2.
The Integrated Global Geodetic Observing System (IGGOS) viewed from the perspective of history 总被引：1，自引：0，他引：1
Towards the end of the 19th century, geodetic observation techniques allowed it to create geodetic networks of continental size. The insight that big networks can only be set up through international collaboration led to the establishment of an international collaboration called “Central European Arc Measurement”, the predecessor of the International Association of Geodesy (IAG), in 1864. The scope of IAG activities was extended already in the 19th century to include gravity.At the same time, astrometric observations could be made with an accuracy of a few tenths of an arcsecond. The accuracy stayed roughly on this level, till the space age opened the door for milliarcsecond (mas) astrometry. Astrometric observations allowed it at the end of the 19th century to prove the existence of polar motion. The insight that polar motion is almost unpredictable led to the establishment of the International Latitude Service (ILS) in 1899.The IAG and the ILS were the tools (a) to establish and maintain the terrestrial and the celestial reference systems, including the transformation parameters between the two systems, and (b) to determine the Earth's gravity field.Satellite-geodetic techniques and astrometric radio-interferometric techniques revolutionized geodesy in the second half of the 20th century. Satellite Laser Ranging (SLR) and methods based on the interferometric exploitation of microwave signals (stemming from Quasars and/or from satellites) allow it to realize the celestial reference frame with (sub-)mas accuracy, the global terrestrial reference frame with (sub-)cm accuracy, and to monitor the transformation between the systems with a high time resolution and (sub-)mas accuracy. This development led to the replacement of the ILS through the IERS, the International Earth Rotation Service in 1989.In the pre-space era, the Earth's gravity field could “only” be established by terrestrial methods. The determination of the Earth's gravitational field was revolutionized twice in the space era, first by observing geodetic satellites with optical, Laser, and Doppler techniques, secondly by implementing a continuous tracking with spaceborne GPS receivers in connection with satellite gradiometry. The sequence of the satellite gravity missions CHAMP, GRACE, and GOCE allow it to name the first decade of the 21st century the “decade of gravity field determination”.The techniques to establish and monitor the geometric and gravimetric reference frames are about to reach a mature state and will be the prevailing geodetic tools of the following decades. It is our duty to work in the spirit of our forefathers by creating similarly stable organizations within IAG with the declared goal to produce the geometric and gravimetric reference frames (including their time evolution) with the best available techniques and to make accurate and consistent products available to wider Earth sciences community as a basis for meaningful research in global change. IGGOS, the Integrated Global Geodetic Observing System, is IAG's attempt to achieve these goals. It is based on the well-functioning and well-established network of IAG services. 相似文献
3.
地震研究中的大地测量 总被引：2，自引：2，他引：0
本文简要回顾了我国大地测量工作者将大地测量技术应用于地震监测和预测的历程。介绍了过去几十年在地震监测和预测中大地测量工作取得的主要进展和成绩,讨论了存在的不足和改进的地方。并且结合近二十年来以3S(GPS、RS、GIS)为代表的高新技术的引入给对地观测技术带来的革命性变化,使得观测结果的精度和时空域中密度大为改观这一事实,对地震研究中的大地测量的发展方向提出了一些看法和建议。 相似文献
4.
Matt A. King Zuheir Altamimi Johannes Boehm Machiel Bos Rolf Dach Pedro Elosegui François Fund Manuel Hernández-Pajares David Lavallee Paulo Jorge Mendes Cerveira Nigel Penna Riccardo E. M. Riva Peter Steigenberger Tonie van Dam Luca Vittuari Simon Williams Pascal Willis 《Surveys in Geophysics》2010,31(5):465-507
The provision of accurate models of Glacial Isostatic Adjustment (GIA) is presently a priority need in climate studies, largely due to the potential of the Gravity Recovery and Climate Experiment (GRACE) data to be used to determine accurate and continent-wide assessments of ice mass change and hydrology. However, modelled GIA is uncertain due to insufficient constraints on our knowledge of past glacial changes and to large simplifications in the underlying Earth models. Consequently, we show differences between models that exceed several mm/year in terms of surface displacement for the two major ice sheets: Greenland and Antarctica. Geodetic measurements of surface displacement offer the potential for new constraints to be made on GIA models, especially when they are used to improve structural features of the Earth’s interior as to allow for a more realistic reconstruction of the glaciation history. We present the distribution of presently available campaign and continuous geodetic measurements in Greenland and Antarctica and summarise surface velocities published to date, showing substantial disagreement between techniques and GIA models alike. We review the current state-of-the-art in ground-based geodesy (GPS, VLBI, DORIS, SLR) in determining accurate and precise surface velocities. In particular, we focus on known areas of need in GPS observation level models and the terrestrial reference frame in order to advance geodetic observation precision/accuracy toward 0.1 mm/year and therefore further constrain models of GIA and subsequent present-day ice mass change estimates. 相似文献
5.
Reiner Rummel 《Journal of Geodynamics》2010,49(3-4):112-115
In 1988 the interdisciplinary role of space geodesy has been discussed by a prominent group of leaders in the fields of geodesy and geophysics at an international workshop in Erice (Mueller and Zerbini, 1989). The workshop may be viewed as the starting point of a new era of geodesy as a discipline of Earth sciences. Since then enormous progress has been made in geodesy in terms of satellite and sensor systems, observation techniques, data processing, modelling and interpretation. The establishment of a Global Geodetic Observing System (GGOS) which is currently underway is a milestone in this respect. Wegener served as an important role model for the definition of GGOS. In turn, Wegener will benefit from becoming a regional entity of GGOS.What are the great challenges of the realisation of a 10?9 global integrated observing system? Geodesy is potentially able to provide – in the narrow sense of the words – “metric and weight” to global studies of geo-processes. It certainly can meet this expectation if a number of fundamental challenges, related to issues such as the international embedding of GGOS, the realisation of further satellite missions and some open scientific questions can be solved. Geodesy is measurement driven. This is an important asset when trying to study the Earth as a system. However its guideline must be: “What are the right and most important observables to deal with the open scientific questions?”. 相似文献
6.
The present article is written in response to the recent call of the United Nations for the enhanced international cooperation of different countries on global geodesy to build the Global Geodetic Reference Frame (GGRF). It reviews historical landmarks in the development of the State Geodetic Reference Frame on the territory of Russia over the last two centuries. It discusses major steps in creating the Russian terrestrial reference frame by both the ground-based and space geodesy methods relying upon the satellite observation techniques. Currently the State Geodetic Reference Frame undergoes a radical improvement in order to effectively implement the potential of modern satellite technologies through the use of the Global Navigation Satellite Systems (GNSS). We outline the current status of the National Geodetic Network in Russia, its hierarchical structure and accuracy. We pay a particular attention to the high-precision State Geodetic Coordinate System (GSK-2011), created simultaneously along with the global reference-ellipsoid, and designed for various types of users to conduct the land surveying and mapping in Russia. We also present the geocentric coordinate system (PZ-90.11) used for navigating space missions, solving various problems of global geodesy, and supporting the continuous operation of GLONASS. 相似文献
7.
Terrestrial reference frame requirements within GGOS perspective 总被引：4，自引：0，他引：4
One of the main objectives of the promising and challenging IAG project GGOS (Global Geodetic Observing System) is the availability of a global and accurate Terrestrial Reference Frame for Earth Science applications, particularly Earth Rotation, Gravity Field and geophysics. With the experience gained within the activities related to the International Terrestrial Reference System (ITRS) and its realization, the International Terrestrial Reference Frame (ITRF), the combination method proved its efficiency to establish a global frame benefiting from the strengths of the various space geodetic techniques and, in the same time, underlining their biases and weaknesses. In this paper we focus on the limitation factors inherent to each individual technique and to the combination, such as the current status of the observing networks, distribution of the co-location sites and their quality and accuracy of the combined frame parameters. Results of some TRF and EOP simultaneous combinations using CATREF software will be used to illustrate the current achievement and to help drawing up future goals and improvements in the GGOS framework. Beyond these technical aspects, the overall visibility and acceptance of ITRS/ITRF as international standard for science and applications is also discussed. 相似文献
8.
《Journal of Geodynamics》2006,41(4-5):363-374
One of the main objectives of the promising and challenging IAG project GGOS (Global Geodetic Observing System) is the availability of a global and accurate Terrestrial Reference Frame for Earth Science applications, particularly Earth Rotation, Gravity Field and geophysics. With the experience gained within the activities related to the International Terrestrial Reference System (ITRS) and its realization, the International Terrestrial Reference Frame (ITRF), the combination method proved its efficiency to establish a global frame benefiting from the strengths of the various space geodetic techniques and, in the same time, underlining their biases and weaknesses. In this paper we focus on the limitation factors inherent to each individual technique and to the combination, such as the current status of the observing networks, distribution of the co-location sites and their quality and accuracy of the combined frame parameters. Results of some TRF and EOP simultaneous combinations using CATREF software will be used to illustrate the current achievement and to help drawing up future goals and improvements in the GGOS framework. Beyond these technical aspects, the overall visibility and acceptance of ITRS/ITRF as international standard for science and applications is also discussed. 相似文献
9.
10.
The International Association of Geodesy has decided to establish an Integrated Global Geodetic Observing System (IGGOS). The objective of IGGOS is to integrate in a well-defined global terrestrial reference frame the three fundamental pillars of geodesy, which are the determination of all variations of surface geometry of our planet (land, ice and ocean surfaces), of the irregularities in Earth rotation sub-divided in changes of nutation, polar motion and spin rate, and of the spatial and temporal variations of gravity and of the geoid. This integration will have to be done with a relative precision of 1 part-per-billion and be maintained stable in space and time over decades. IGGOS will quantify on a global scale surface changes, mass anomalies, mass transport and mass exchange and exchange in angular momentum in system Earth. It will be a novel and unique contribution to Earth system and Global Change research. It is intended to make IGGOS part of the Integrated Global Observing Strategy (IGOS). 相似文献
11.
《Journal of Geodynamics》2006,41(4-5):357-362
The International Association of Geodesy has decided to establish an Integrated Global Geodetic Observing System (IGGOS). The objective of IGGOS is to integrate in a well-defined global terrestrial reference frame the three fundamental pillars of geodesy, which are the determination of all variations of surface geometry of our planet (land, ice and ocean surfaces), of the irregularities in Earth rotation sub-divided in changes of nutation, polar motion and spin rate, and of the spatial and temporal variations of gravity and of the geoid. This integration will have to be done with a relative precision of 1 part-per-billion and be maintained stable in space and time over decades. IGGOS will quantify on a global scale surface changes, mass anomalies, mass transport and mass exchange and exchange in angular momentum in system Earth. It will be a novel and unique contribution to Earth system and Global Change research. It is intended to make IGGOS part of the Integrated Global Observing Strategy (IGOS). 相似文献
12.
13.
华北地区大地震矩释放率和GPS应变率的一致性研究 总被引：2，自引：0，他引：2
GPS测量技术可以在较大地区范围内获得高精度地壳形变速率。稳定的应变速率提供了精确确定地震活动率的机会。本文运用Kostrov(1974)的公式将经平滑的华北地区应变速率转化为矩释放率，并与运用1303年洪洞地震以来的地震目录计算的矩释放率进行比较，发现两者之比南北向为60．6％，东西向为68．9％，北东剪切分量为104．1％。近似为1的比率表明了GPS测量结果的可靠性。这个结果对结合历史地震及大地形变测量估计矩释放进行地震危险性评估具有一定参考意义。 相似文献
14.
地球参考框架是国家重要的空间基础设施,是地球上人类所有活动的空间参考基准。本文首先阐述了国际地球参考框架（International Terrestrial Reference Frame,ITRF）的发展现状,重点评述了ITRF的建立与维持,针对ITRF的发展现状提出了存在的问题;其次,以ITRF与2000国家大地坐标系（China Geodetic Coordinate System 2000,CGCS2000）的关系及现状为切入点,探讨了我国建立北斗坐标系的必要性,介绍了建立北斗坐标系的基本思路以及初始实现;最后,对地球参考框架的未来发展进行了展望。 相似文献
15.
16.
地球重力学是研究重力场时空分布及其物理机制的一门学科．地球重力场的空间分布通常可用于三个方面：一是空间科学和大地测量学，主要是利用地表的重力观测对在其上测得的几何量加以归算，以及给出重力场的高空赋值以修正卫星和近地飞行器的轨道；二是反演地球内部结构，主要是三维密度的不均匀分布，并对诸如地慢对流等作约束；三是勘探在时间变化方面，最主要影响来自固体潮，当然还有许多内部力源导致动力学效应．本文着重对我国大地重力研究和固体潮研究的进展作一回顾． 相似文献
17.
《中国科学:地球科学(英文版)》2021,(8)
The ice flow velocity is a basic feature of glaciers and ice sheets. Measuring ice flow velocities is very important for estimating the mass balance of ice sheets in the Arctic and Antarctic. Traditional methods for measuring ice flow velocity include the use of stakes, snow pits and on-site geodetic GPS and remote sensing measurement methods. Geodetic GPS measurements have high accuracy, but geodetic GPS monitoring points only sparsely cover the Antarctic ice sheets. Moreover, the resolution and accuracy of ice flow velocities based on remote sensing measurements are low. Although the accuracy of the location data recorded by the navigation-grade GPS receivers embedded in short-period seismographs is not as good as that of geodetic GPS,the ice flow velocity can be accurately measured by these navigation-grade GPS data collected over a sufficiently long period. In this paper, navigation-grade GPS location data obtained by passive seismic observations during the 36 th Chinese National Antarctic Research Expedition were used to accurately track the movement characteristics of the ice sheet in the Larsemann Hills of East Antarctica and the Taishan Station area. The results showed that the ice sheet in the two study areas is basically moving northwestward with an average ice flow velocity of approximately 1 m mon-1. The results in the Taishan Station area are basically consistent with the geodetic GPS results, indicating that it is feasible to use the embedded GPS location data from shortperiod seismographs to track the movement characteristics of ice sheets. The ice flow characteristics in the Larsemann Hills are more complex. The measured ice flow velocities in the Larsemann Hills with a resolution of 200 m help to understand its characteristics. In summary, the ice flow velocities derived from GPS location data are of great significance for studying ice sheet dynamics and glacier mass balance and for evaluating the systematic errors caused by ice sheet movements in seismic imaging. 相似文献
18.
《Journal of Geodynamics》2006,41(4-5):394-399
We discuss how the geophysical fluids affect the Earth orientation parameters (EOP) and in particular polar motion and nutation. We show that the Earth orientation modeling is a perfect example of the integrated approach recommended by GGOS. GGOS considers the Earth system as a whole, including the solid Earth as well as the fluid components; geodesy observes and models the dynamics inside this system through the static and time-varying gravity field, the station displacements, and the Earth orientation parameters and the associated length-of-day variation, nutation and polar motion. Global-scale transfer in the Earth system and its geodetic consequences is proposed to be the central theme of GGOS. We show that the Earth orientation parameters perfectly fit this theme. 相似文献
19.
We discuss how the geophysical fluids affect the Earth orientation parameters (EOP) and in particular polar motion and nutation. We show that the Earth orientation modeling is a perfect example of the integrated approach recommended by GGOS. GGOS considers the Earth system as a whole, including the solid Earth as well as the fluid components; geodesy observes and models the dynamics inside this system through the static and time-varying gravity field, the station displacements, and the Earth orientation parameters and the associated length-of-day variation, nutation and polar motion. Global-scale transfer in the Earth system and its geodetic consequences is proposed to be the central theme of GGOS. We show that the Earth orientation parameters perfectly fit this theme. 相似文献
20.
地球南北半球的非对称性 总被引：12，自引：1，他引：12
依据新的计算分析和空间观测数据,进一步论述了地球南北半球的非对称性. 全球热散失量的计算得出,南半球高出北半球33髎;南半球地幔热散失量是北半球的2倍. 比较南北半球S波速度分布,得出南半球的上地幔为低速、高温,北半球的上地幔为高速、低温. 计算地幔各层的质心位置发现,地球的质心偏于北半球. 计算地球经、纬圈长度的年变化率表明,南半球在扩张,北半球在收缩. 用空间大地测量数据的检测结果证实,南半球处于扩张状态,北半球处于压缩状态. 对地球的非对称性作了初步的动力学解释. 相似文献