Energy integral method for gravity field determination from satellite orbit coordinates   总被引：22，自引：1，他引：21  

P. N. A. M. Visser  N. Sneeuw  C. Gerlach 《Journal of Geodesy》2003,77(3-4):207-216

A fast iterative method for gravity field determination from low Earth satellite orbit coordinates has been developed and implemented successfully. The method is based on energy conservation and avoids problems related to orbit dynamics and initial state. In addition, the particular geometry of a repeat orbit is exploited by using a very efficient iterative estimation scheme, in which a set of normal equations is approximated by a sparse block-diagonal equivalent. Recovery experiments for spherical harmonic gravity field models up to degree and order 80 and 120 were conducted based on a 29-day simulated data set of orbit coordinates. The method was found to be very flexible and could be easily adapted to include observations of non-conservative accelerations, such as (to be) provided by satellites like CHAMP, GRACE, and GOCE. A serious drawback of the method is its large sensitivity to satellite velocity errors. Existing orbit determination strategies need to be altered or augmented to include algorithms that focus on optimizing the accuracy of estimated velocities.  相似文献   

有机试剂萃取比色法直接测定岩石、水系沉积物和土样中三价铁     

崔沂涛  王家圻 《国土资源》1988,(3)

本文探讨了直接测定三价铁的萃取比色法。该方法基于Fe~(3+)与8-羟基喹啉形成的络合物能被萃取入氯仿层,而在同一体系中的Fe~(2+)与邻菲咯啉形成的络合物却不然,这就使比色法测定有机相中的三价铁成为可能.本方法重现性好,准确度高,RSD％(n=10):1.44,适用于岩石、水系沉积物和土样中三价铁的测定。  相似文献   

用PANDA对GPS和CHAMP卫星精密定轨   总被引：5，自引：3，他引：2  

赵齐乐  刘经南  葛茂荣  施闯  杜瑞林 《大地测量与地球动力学》2005,25(2):113-117

介绍了武汉大学自主研制的卫星导航系统综合处理软件PANDA；利用全球45个IGS站以及CHAMP卫星星载GPS数据．在不同条件下分别实现了GPS卫星的精密定轨．以及CHAMP卫星和GPS导航星座联合精密定轨。结果与IGS的最终精密星历以及GFZ提供的CHAMP卫星精密轨道的比较说明：PANDA软件求解的GPS导航星座和CHAMP卫星轨道精度处于同等水平。  相似文献   

Orbit Determination Using Satellite—to—Satellite Tracking Data   总被引：3，自引：0，他引：3  

Ying－ChunLiu LinLiu 《中国天文和天体物理学报》2001,1(3):281-286

1 INTRODUCTIONThe tracking arc-length should be increased in order to approve the accuracy in orbitdetermination of LEO (Low Earth Orbit) satellites. The local ground-based tracking networkdoes not provide sufficient orbit coverage for the user satellites. The most promising methodis to use high orbiting satellites, such as GPS and TDRS, as trackers to observe the usersatellites. For examPle, tWO geosynclironous satellites could cover more than 85% of the orbitof any given user sate…  相似文献   

Age and growth of the common goby, Pomatoschistus microps, on the south coast of England     

M.M. Fouda  P.J. Miller 《Estuarine, Coastal and Shelf Science》1981,12(2):121-IN1

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钼－氨三乙酸－溴邻苯三酚红－溴化十六烷基三甲基铵体系的显色反应及其应用     

罗宗铭  钟卓荣 《岩矿测试》1994,(3)

在ｐＨ２．５的氯乙酸缓冲介质中，有溴化十六烷基三甲基铵（ＣＴＭＡＢ）存在下，Ｍｏ（Ⅵ）与氨三乙酸（ＮＴＡ）及溴邻苯三酚红（ＢＰＲ）形成胶束混配配合物，该配合物最大吸收波长在６００ｎｍ，摩尔吸光系数为７．２７×１０￣４Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１），配合物组成为Ｍｏ（Ⅵ）：ＮＴＡ：ＢＰＲ：ＣＴＭＡＢ＝１：１：２：４。Ｍｏ（Ⅵ）量在０～１．０ｇ／ｍｌ范围内符合比尔定律。由于ＮＴＡ的存在，改善了方法的选择性，可直接分光光度测定矿石及钢中微量Ｍｏ。  相似文献   

J77大气模型的修订和应用   总被引：1，自引：0，他引：1  

汤锡生 《天文学报》1995,36(4):400-411

Ｊａｃｃｈｉａ １９７７大气模型（简称Ｊ７７）发表后，Ｊａｃｃｈｉａ本人对模型进行了重大修订，这两个修订都是关于地磁活动引起的大气密度变化，为了比较分析修订后模型的改进情况，本文作者更新了Ｊ７７模型的软件，对每一步修订进行了详细的数值试验，并将其应用于高度为８００公里ＥＲＳ－１卫星的轨道计算，结果表明：修订后的Ｊ７７模型比其它大气模型在测轨精度上有明显改善。  相似文献   

On-the-fly GPS-based attitude determination using single- and double-differenced carrier phase measurements   总被引：4，自引：2，他引：2  

Y.?LiEmail author  K.?Zhang  C.?Roberts  M.?Murata 《GPS Solutions》2004,8(2):93-102

Carrier phase measurements are primary observations for GPS attitude determination. Although the satellite-related errors can be virtually eliminated by forming single differences, the baseline-related errors such as line biases are still present in the single-differenced carrier phase measurements. It is, therefore, difficult to resolve the single-differenced integer ambiguities due to the line biases. By forming double differences, the line biases of the single-differenced carrier phase measurements can be effectively removed. However, the main disadvantages of this method lie in the fact that the double-differenced measurements are mathematically correlated and consequently the attitude obtained from the double differences is noisy. This paper presents a new algorithm through which both single and double differences are used simultaneously to resolve these problems in real-time. The solution of the integer ambiguities can be obtained by searching for the most likely grid point in the attitude domain that is independent of the correlation with the double differences. Next, the line biases and corresponding single difference integer ambiguities can be resolved on the fly by using the noisy attitude solution obtained from the previous double difference procedure. In addition, the relationship between the physical signal path difference and the line bias is formed. A new method is also applied to derive the attitude angles through finding the optimal solution of the attitude matrix element. The proposed new procedure is validated using ground and flight tests. Results have demonstrated that the new algorithm is effective and can satisfy the requirement of real-time applications.  相似文献   

GPS-Based On-Board Orbit Determination of a Satellite Using Extended H ∞ Filtering Algorithms     

Jinlu Kuang  Soonhie Tan  Youfa Wang 《Celestial Mechanics and Dynamical Astronomy》2004,88(2):103-122

In this paper the extended H filtering algorithms for the design of the GPS-based on-board autonomous navigation system for a low earth orbit (LEO) satellite are introduced. The dynamic process models for the estimation of position, velocity and acceleration from the GPS measurements are established. The nominal orbit of the small LEO satellite is determined by using the 7th–8th order Runge—Kutta algorithms. Three filtering approaches are applied to smooth the orbit solutions, respectively, based upon the simulated GPS pseudo range observables using the Satellite Navigation Tool Box. The simulation shows that the observed orbit errors obtained by using the extended H filtering algorithms can be reduced to a lower level than the observed orbit errors in the sense of RMS within 12 h of tracking time by using the H filtering algorithms and the extended Kalman filtering algorithms under the appropriately designed parameters. Based upon the position errors predicted by the three filtering algorithms after the last observation, we find that the extended H filtering algorithm provides the least position errors of the user satellite.This revised version was published online in October 2005 with corrections to the Cover Date.  相似文献   

The effect of topographical and atmospheric masses on spaceborne gravimetric and gradiometric data   总被引：2，自引：0，他引：2  

P. Novák  E. W. Grafarend 《Studia Geophysica et Geodaetica》2006,50(4):549-582

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