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941.
Toshio Fukushima 《Journal of Geodesy》2006,79(12):689-693
By using Halley’s third-order formula to find the root of a non-linear equation, we develop a new iterative procedure to solve an irrational form of the “latitude equation”, the equation to determine the geodetic latitude for given Cartesian coordinates. With a limit to one iteration, starting from zero height, and minimizing the number of divisions by means of the rational form representation of Halley’s formula, we obtain a new non-iterative method to transform Cartesian coordinates to geodetic ones. The new method is sufficiently precise in the sense that the maximum error of the latitude and the relative height is less than 6 micro-arcseconds for the range of height, −10 km ≤ h ≤ 30,000 km. The new method is around 50% faster than our previous method, roughly twice as fast as the well-known Bowring’s method, and much faster than the recently developed methods of Borkowski, Laskowski, Lin and Wang, Jones, Pollard, and Vermeille. 相似文献
942.
Analyses and Solutions of Errors on GPS/GLONASS Positioning 总被引:1,自引:0,他引:1
ZHANGYongjun WANGZemin 《地球空间信息科学学报》2002,5(2):6-12
This paper focuses mainly on the major errors and their reduction approaches pertaining to combined GPS/GLONASS positioning.To determine thd difference in the time reference systems,different receiver clock offsets are introduced with respect to GPS and GLONASS system time.A more desirable method for introducing a independent unknown parameter of fifth receiver,which can be canceled out when forming difference measurements,is discussed.The error of orbit integration and the error of transformation parameters are addressed in detail.Results of numerical integration are give.To deal with the influence of ionospheric delay,a method for forming dual-frequency ionospheric free carrier phase measurements is detailed. 相似文献
943.
Wang Weidong Bai Kezhuang Zu Donglin Bao Shanglian Jerome Z. Liang )The Biomedical engineering research office Chinese PLA General Hospital Beijing )Beijing document service Beijing )The 《CT理论与应用研究》1998,7(4):44-49
许多共振成像(MRI)的应用,要求人体组织磁化强度的空间分布Fourier变换的幅度和相位的精确分离,及利用正交双通道采集时间和空间高分辨图象序列。在传统的基于Fourier变换的成象方法中,图象序列从一帧空间编码独立地重建得到,因此给定空间分辨率的情况下,每帧空间编码的数量限制了图象序列的时间分辨力;又常通过牺牲空间分辨率来提高图象序列的空间分辨录。由于传统Fourier变换的核函数是线性相位,若变换MRI技术必须很好地满足主磁场均匀性和梯度场线性的条件,因此传统Fourier变换成象方法对临床应用中常出现MR信号相位失真极为敏感。本文提出:利用主磁场中组织的磁化强度不变,能很好消除图象的相位失真。 相似文献
944.
945.
946.
对非量测用摄影机所摄影像的解析处理 ,控制点起着不可缺少的桥梁作用 ,控制点的数量和分布形式将直接影响平差结果的可靠性和精度。文中利用手持式 1 2 0普通相机 ,从可靠性和精度上 ,就基于直接线性变换算法中 ,对控制点的优化设计问题进行了实验分析 ,得出了有意义的结论。 相似文献
947.
Fu Baopu 《Acta Meteorologica Sinica》1998,12(2):235-246
In this paper a model, simulating the transformation of airflow passing through waters, ispresented and examined by the data observed over the Dazong Lake in Xinghua County of JiangsuProvince. Calculation results show that the theoretical transformations of airflow are in goodagreement with observations. 相似文献
948.
由国家地震局地球物理研究所承担的“MTS-100T伺服试验机改造”课题,对震源物理实验室进行了实验系统改造。该文简要介绍了该课题所完成的主要工作及其应用情况,包括:MTS-100T伺服试验机控制系统、16通道高速数据采集系统、激光散斑图干涉仪。 相似文献
949.
紧支小波变换算法实现及边界点处理 总被引:3,自引:2,他引:1
本文讨论了紧支小波变换的具体实现方法,并对其边界点进行了合理的处理,使得对信号的分解和重构具有很高的保真度。 相似文献
950.
A most distinctive feature of the settlement pattern of the Brasov area is the extreme dispersal of mixed farming encountered
in the western extreme of the county to the north and south of Zarnesti: the Bran and Poiana Marului areas. Here a system
of peasant subsistence farming developed in a political borderland between the Habsburg and Ottoman Empires. Despite feudal
pressures, the peasantry took all available opportunities to extend their independence including elaborate transhumance systems.
And after seeing transfrontier commerce as a source of plunder, in the tradition of Balkan highway robbery within relatively
unregulated spaces, the peasantry has profited through employment in factories, particularly during the communist period.
However, the current recession in manufacturing is throwing the rural population back on limited land resources. Although
farming assumes an important subsistence role which contributes to stability, the long-term survival of these communities
will depend on new sources of income. Rural tourism has considerable potential and a promising start has been made in Bran.
There are, however, constraints on the further development of the business and great attention will have to be given to the
conservation of the environment in both the Bucegi Mountains and the Piatra Craiului where national park status is proposed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献