见 http://www.esa.int/SPECIALS/GOCE/SEM1AK6UPLG_0.html ESA 的文字说明 Best view yet of global gravity 31 March 2011 After just two years in orbit, ESA's GOCE satellite has gathered enough data to map Earth's gravity with unrivalled precision. Scientists now have access to the most accurate model of the 'geoid' ever produced to further our understanding of how Earth works. The new geoid was unveiled today at the Fourth International GOCE User Workshop hosted at the Technische Universitt München in Munich, Germany. Media representatives and scientists from around the world have been treated to the best view yet of global gravity. The geoid is the surface of an ideal global ocean in the absence of tides and currents, shaped only by gravity. It is a crucial reference for measuring ocean circulation, sea-level change and ice dynamics – all affected by climate change.
Impact of GPS antenna phase center variations on precise orbits of the GOCE satellite 以slr geodsy google 得到 References and further reading may be available for this article. To view references and further reading you must purchase this article. H. Bock , a , , A. Jggi a , U. Meyer a , R. Dach a and G. Beutler a a Astronomical Institute, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland Received 6 October 2010; revised 14 January 2011; accepted 17 January 2011. Available online 23 January 2011. Abstract The first European Space Agency Earth explorer core mission GOCE (Gravity field and steady-state Ocean Circulation Explorer) has been launched on March 17, 2009. The 12-channel dual-frequency Global Positioning System receiver delivers 1 Hz data and provides the basis for precise orbit determination (POD) on the few cm-level for such a very low orbiting satellite (254.9km). As a member of the European GOCE Gravity Consortium, which is responsible for the GOCE High-level Processing Facility (HPF), the Astronomical Institute of the University of Bern (AIUB) provides the Precise Science Orbit (PSO) product for the GOCE satellite. The mission requirement for 1-dimensional POD accuracy is 2cm. The use of in-flight determined antenna phase center variations (PCVs) is necessary to meet this requirement. The PCVs are determined from 154 days of data and the magnitude is up to 3-4cm. The impact of the PCVs on the orbit determination is significant. The cross-track direction benefits most of the PCVs. The improvement is clearly seen in the orbit overlap analysis and in the validation with independent Satellite Laser Ranging (SLR) measurements. It is the first time that SLR could validate the cross-track component of a LEO orbit. Keywords: GOCE; phase center variations; GPS; Low Earth Orbiters; precise orbit determination; SLR http://www.sciencedirect.com/science?_ob=ArticleURL_udi=B6V3S-5211JH1-2_user=10_coverDate=01%2F23%2F2011_rdoc=1_fmt=high_orig=search_origin=search_sort=d_docanchor=view=c_searchStrId=1629092497_rerunOrigin=scholar.google_acct=C000050221_version=1_urlVersion=0_userid=10md5=1419709f4c242f9ae7dba0656dff8b50searchtype=a
以下资料说是 : 国际重力界期盼已久的 GOCE 卫星 , 要在这个月发射 . 由于等米 (----GOCE 获取的实际数据 ) 下锅 , 众多研究者已经消磨了些许时光 , 处理 GOCE 获取的重力梯度 ( 重力位的二阶导数 ) 的软件已经有 N 种 . 只要数据有了 , 相信会引发一个股论文潮 . 不会再总是以模拟数据进行模拟计算了 , 这样的结果才让人更兴奋 . 实测数据将检验以下三个 预期结果 : 以毫伽 (1 mGal (1 mGal = 10 5 ms 2 ) ,ms 2 即米 / 秒的平方 ) 的精度确定重力异常 . 以 1 -2 厘米 的精度确定大地水准面 . 实现 100 公里 的空间分别率 . 以下资料来自欧洲空间局网站 http://www.esa.int/esaLP/ESAYEK1VMOC_LPgoce_0.html ESA's gravity mission GOCE Planned for launch in March 2009, ESA's Gravity field and steady-state Ocean Circulation Explorer (GOCE) has been developed to bring about a whole new level of understanding of one of the Earth's most fundamental forces of nature the gravity field. Dubbed the 'Formula 1' of spacecrafts, this sleek high-tech gravity satellite embodies many firsts in terms of its design and use of new technology in space to map Earth's gravity field in unprecedented detail. As the most advanced gravity space mission to date, GOCE will realise a broad range of fascinating new possibilities for the fields of oceanography, solid Earth physics, geodesy and sea-level research, and significantly contribute to furthering our understanding of climate change. Although invisible, gravity is a complex force of nature that has an immeasurable impact on our everyday lives. It is often assumed that the force of gravity on the surface of the Earth has a constant value, but in fact the value of 'g' varies subtly from place to place. These variations are due to a number of factors such as the rotation of the Earth, the position of mountains and ocean trenches and variations in density of the Earth's interior. 橙色部分大意 : 尽管重力不可见 , 这种复杂的力 , 一直在 ( 难以估量地 ) 影响着我们的生活 . 人们常假定重力的数值恒定 , 其实它 ( 以 g 表示 ) 随空间的变化在奇妙地变化着 , 影响因素有地球的自转 , 山脉海沟的位置 , 以及地球内部密度的变化等 . GOCE to map gravity as never before Over its lifetime of about 20 months, GOCE will map these global variations in the gravity field with extreme detail and accuracy. This will result in a unique model of the geoid, which is the surface of equal gravitational potential defined by the gravity field crucial for deriving accurate measurements of ocean circulation and sea-level change, both of which are affected by climate change. GOCE-derived data is also much needed to understand more about processes occurring inside the Earth and for use in practical applications such as surveying and levelling. GOCE takes six simultaneous measurements of the gravity field Since the gravitational signal is stronger closer to Earth, the 'arrow-like', five-metre long GOCE satellite has been designed to cut through of what remains of the Earth's atmosphere at just 250 km above the surface of the planet. This low-orbiting spacecraft is the first mission to employ the concept of gradiometry - the measurement of acceleration differences over short distances between an ensemble of proof masses inside the satellite. GOCE is equipped with three pairs of ultra-sensitive accelerometers arranged in three dimensions that respond to tiny variations in the 'gravitational tug' of the Earth as it travels along its orbital path. Because of their different position in the gravitational field they all experience the gravitational acceleration of the Earth slightly differently. The three axes of the gradiometer allow the simultaneous measurement of six independent but complementary components of the gravity field. Although the gradiometer forms the heart of the satellite, to measure gravity there can be no interference from moving parts so the entire spacecraft is actually one extremely sensitive measuring device. Mission objectives to determine gravity-field anomalies with an accuracy of 1 mGal (where 1 mGal = 10 5 ms 2 ). to determine the geoid with an accuracy of 1 -2 cm . to achieve the above at a spatial resolution better than 100 km .
With a completely new generation of low-orbiting satellites, equipped with highly precise inter-satellite and accelerometry-instrumentation observing the Earth gravitational field and its temporal variability, space geodesy has entered the 21 century. Section 1.2 had a leading role in setting up the operational processing systems for CHAMP (lauch July 2000) and GRACE (lauch March 2002) and is handling a great deal of the data preprocessing, precision orbit determination and generation of monthly gravity field solutions for both missions on a routine basis. Section 1.2 is also heavily engaged in the preparation of upcoming national (TerraSAR, Tandem-X) and European missions (GOCE, SWARM, GRACE-follow on). Section 1.2 together with Section 1.3 in addition is involved in the analysis of historical tracking data including the first GFZ geopotential satellite GFZ-1, and in the analysis of gravity data over land and oceans. By combination of different data subsets the EIGEN satellite and combination models are computed. Section 1.2 is involved in research and development activities as well as in operational and coordination tasks for various gravity and altimetry missions and the related tracking support. Research is done primarily in support of precision orbit determination of near Earth satellites, high resolution gravity field modelling and the use of satellite altimetry for oceanography and geodetic / geophysical applications. 来源:http://www.gfz-potsdam.de/pb1/op/index_GRAM.html
标签: GOCE
