共查询到20条相似文献，搜索用时 31 毫秒
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E.D. Kuznetsov 《Planetary and Space Science》1997,45(12):1595-1606
The equation for calculation of the required accuracy of the perturbing bodies motion theories is obtained. The equation relates the accuracy required to take into account perturbing acceleration, acting on the perturbed body, with the accuracy of the motion theory of the perturbing body. The solutions for estimation of the required accuracy both for the inner and the external cases in the spherical coordinates are coincided. The solution for the calculation of the required accuracy for the general case (combining the inner and the external cases) in Cartesian coordinates is obtained. The special cases for the solution in Cartesian coordinates are studied. As an example, the estimations of the required accuracy of the motion theories of the solar system planets for some perturbed bodies (the near-Earth asteroid 4179 Toutatis, the main belt asteroid 208 Larcimosa, the trojan asteroid 588 Achilles, the centaur asteroid 5145 Pholus, the Kuiper belt asteroid 1995 QZ9, the comet Halley) are obtained. The conditions of the use of the obtained results are discussed. 相似文献
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SGP4/SDP4模型精度分析 总被引：2，自引：0，他引：2
本文基于最新发布的SGP4/SDP4(Simplified General Perturbation Version 4/Simplified Deep-space Perturbation Version 4)模型设计了一套定轨方案,从空间目标库中挑选出不同类型和轨道参数的1120个目标进行计算,定量给出了SGP4/SDP4模型处理不同类型空间目标的定轨预报精度.结果表明:近地目标定轨精度为百米量级;半同步和同步轨道定轨精度平均为0.7和1.9km.椭圆轨道目标的定轨精度与偏心率有关,除少数e>0.8的椭圆轨道目标,绝大多数椭圆轨道目标定轨误差均小于10km.用SGP4/SDP4模型对近地目标预报3天,半同步轨道预报30天,同步轨道预报15天,椭圆轨道预报1天,预报误差一般不超过40km. 相似文献
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在导航系统中,基准站配置的优劣直接关系到定位的精度及系统的可用性,对利用卫星电视系统进行导航可能采用的几种基准站配置进行了讨论,并对具体问题进行了分析计算,分析认为解决好基准站配置,合理地组合导航系统,可有效地提高定位的精度及系统的可用性。 相似文献
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针对目前极移最小二乘(Least Square, LS)+自回归(AutoRegressive, AR)预报模型的单一数据选取方案, 提出分别考虑LS模型数据量和AR残差数据量的组合数据模式, 并对极移预报时单一数据和组合数据预报结果精度进行分析, 探讨模型输入数据量对极移预报精度的影响. 结果表明, 模型输入数据量的变化对极移预报结果影响较大. 采用组合数据预报的方式相比较于单一数据量预报方式精度更高, 特别是针对30--360 d跨度内的中长期预报, 组合数据量的极移预报精度可比单一数据量预报精度有较大改善. 结论证明组合数据在极移预报时具有一定的优势, 可为以后极移预报数据量选取提供一定的借鉴参考意义. 相似文献
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P. K. Seidelmann 《Celestial Mechanics and Dynamical Astronomy》1993,56(1-2):1-12
Planetary and satellite theories have been historically and are presently intimately related to the available computing capabilities, the accuracy of observational data, and the requirements of the astronomical community. Thus, the development of computers made it possible to replace planetary and lunar general theories with numerical integrations, or special perturbation methods. In turn, the availability of inexpensive small computers and high-speed computers with inexpensive memory stimulated the requirement to change from numerical integration back to general theories, or representative ephemerides, where the ephemerides could be calculated for a given date rather than using a table look-up process. In parallel with this progression, the observational accuracy has improved such that general theories cannot presently achieve the accuracy of the observations, and, in turn, it appears that in some cases the models and methods of numerical integration also need to be improved for the accuracies of the observations. Planetary and lunar theories were originally developed to be able to predict phenomena, and provide what are now considered low accuracy ephemerides of the bodies. This proceeded to the requirement for high accuracy ephemerides, and the progression of accuracy improvement has led to the discoveries of the variable rotation of the Earth, several planets, and a satellite. By means of mapping techniques, it is now possible to integrate a model of the motion of the entire solar system back for the history of the solar system. The challenges for the future are: Can general planetary and lunar theories with an acceptable number of terms achieve the accuracies of observations? How can numerical integrations more accurately represent the true motions of the solar system? Can regularly available observations be improved in accuracy? What are the meanings and interpretations of stability and chaos with respect to the motions of the bodies of our solar system? There has been a parallel progress and development of problems in dealing with the motions of artificial satellites. The large number of bodies of various sizes in the limited space around the Earth, subject to the additional forces of drag, radiation pressure, and Earth zonal and tesseral forces, require more accurate theories, improved observational accuracies, and improved prediction capabilities, so that potential collisions may be avoided. This must be accomplished by efficient use of computer capabilities. 相似文献
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Walter Petry 《Astrophysics and Space Science》1992,189(1):63-77
The post-Newtonian approximation of the gravitational field of a perfect fluid for a previously stated theory of gravitation in flat space-time is studied. The conservation laws of energy-momentum and angular-momentum are derived and the equivalence of the conservation law of energy-momentum and the equations of motion is shown to the studied accuracy. The equations of motion are stated. All the results of the post-Newtonian approximation of the gravitation theory in flat space-time and of the general theory of relativity, as considered by Will in his famous book, agree to the studied accuracy. 相似文献
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Five methods for numerically integrating stellar orbits in a time-independent, steady potential are compared in efficiency and accuracy. The methods are: Fehlberg's (1972) treatment of the Runge-Kutta method, Krogh's (1971) variable-order Adam's method, an extrapolation method described by Stoer (1974) and two orders of the implicit single-sequence method of Everhart (1974). It is found that Fehlberg's 6th-order Runge-Kutta is the fastest but also the least accurate. The new method of Everhart seems a good compromise between efficiency and accuracy in this problem. 相似文献
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The satellite-borne GPS receivers dedicated to precise orbit determination are now being carried by more and more low earth orbit (LEO) satellites and the satellite-borne GPS has become one of the main means for the precise orbit determination of low earth orbit satellites. The accuracy of satellite-borne GPS precise orbit determination depends on the accuracies of the GPS ephemeris and the clock error. Based on the orbit determination function of SHORDEIII zero-difference dynamics and using the observational data obtained by the GRACE satellites for the week from 2005 August 1 to 7 as an example, three versions of GPS ephemerides (igs, igr and igu) are used to carry out orbit determination under the same conditions and to estimate the effect of the GPS ephemeris accuracy on the accuracy of orbit determination of low earth orbit satellites. Our calculated results show that the two ephemerides, igs and igr, are equivalent to each other in orbit determination accuracy (about 9.5 cm), while igu is slightly less accurate, at about 10.5 cm. The effect produced by the data of the high frequency GPS satellite clock error on the accuracy of orbit determination is 1–6 cm. 相似文献
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Multirevolution methods allow for the computation of satellite orbits in steps spanning many revolutions. The methods previously discussed in the literature are based on polynomial approximations, and as a result they will integrate exactly (excluding round-off errors) polynomial functions of a discrete independent variable. Modified methods are derived that will integrate exactly products of linear and periodic functions. Numerical examples are given that show that these new methods provide better accuracy for certain satellite problems. It is also shown that information obtained from an approximate analytical solution of the satellite equations of motion, may be used to increase the accuracy and/or efficiency of the multirevolution integration. 相似文献
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Xiao-Qiang Tang Jin-Song Wang Qi-Ming Wang Department of Precision Instruments Tsinghua University Beijing National Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2003,3(5):478-490
We propose a spatial three-degree-of-freedom (DOF) parallel mechanism combining two degrees of rotations and one degree of translation to support the active reflector units of a large spherical radio telescope. The kinematics, workspace and accuracy of the mechanism are analyzed. One-dimensional and two-dimensional fitting errors to the working region of active reflector are investigated. Dimensional parameters of the mechanism and active reflector unit are examined with respect to the requirement of fitting accuracy. The result of accuracy analysis shows the effectiveness and feasibility of the proposed mechanism, and gives a design rule to guarantee the highest working frequency required by large radio telescope. 相似文献
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本文简要提出了视频ＣＣＤ在天体定位方面的两个问题；比例尺和定位精度的问题。并提出了两个确定比例尺的方法。本文认为影响比例尺和定位精度的主要因素是与所使用的图象板相关。 相似文献
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N. Borderies 《Celestial Mechanics and Dynamical Astronomy》1977,16(3):291-308
This paper deals with the Adams-Moulton-Cowell multistep integrator, as described by Oestwinter and Cohen (1972). In order to evaluate the accuracy of the method, we started to test it in the case of the unperturbed two-body motion; numerical instability may arise by integrating first order systems. The accuracy is improved by applying a Sundmann transformation of the independent variable. The algorithm is then modified such that the equations of pure keplerian motion are integrated with respect to the new independent variable without truncation error; numerical experiments show the considerable improvement of accuracy and the reduction of computing time for Keplerian motion.If terms of the disturbing function of the Earth are added to the central potential, the time-transformation is less effective. With a modification of this time-transformation as given by Moynot in 1971, it is possible to reduce the propagation of the truncation error in the J2 problem. 相似文献
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A. I. Zacharov N. L. Krusanova I. V. Moskatiniev M. E. Prohorov O. Y. Stekol’shchikov V. K. Sysoev M. S. Tuchin A. D. Yudin 《Solar System Research》2018,52(7):636-643
Modern star trackers are based on photodetector arrays such as CCD or CMOS arrays. The accuracy of commercially available devices is ~1–3 arcseconds. However, the development of the space industry calls for higher orientation accuracies, which are needed in laser space communications, monitoring of near-Earth space and space debris, high-precision global mapping, and remote sensing of the Earth. The problems associated with enhancing the accuracy of modern star trackers are discussed. 相似文献
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Jeremy J. Davis Daniele Mortari Christian Bruccoleri 《Celestial Mechanics and Dynamical Astronomy》2010,108(1):59-72
Seven sequential starter values for solving Kepler’s equation are proposed for fast orbit propagation. The proposed methods
have constant complexity (not iterative), do not require pre-computed data, and can be implemented in just a few lines of
code. The resulting sequential orbit propagation techniques can be done at different levels of accuracy and speed, depending
essentially on the value of orbit eccentricity. Accuracy and algorithmic complexity are evaluated for all the proposed approaches
and compared with several existing single-point techniques to solve Kepler’s equation. The new methods obtain improved accuracy
at lower computational cost as compared to the best existing methods. 相似文献
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The effect of micrometeorite impacts upon the surface of a spacecraft on the accuracy of astrometric measurements made by scanning with instruments onboard the spacecraft is considered. This effect is shown to be marginal for HIPPARCOS measurements. However, disregarding this kind of effect for all the currently projected spacecraft may result in the declared measurement accuracy being unachievable. Spacecraft maintaining constant spatial orientation during measurements are essentially not subject to the errors caused by collisions with micrometeorites. 相似文献
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V. G. Gavryusev E. A. Gavryuseva 《Monthly notices of the Royal Astronomical Society》2000,317(3):569-580
Using a 1154 d long measurement of solar oscillations, obtained by the Global Oscillation Network Group from 1995 June 10 to 1998 August 6, we study the dependence of the accuracy of radial p-mode parameters on the duration of the observations. It is shown that relatively rare pulses of large power lead to the decrease of the accuracy achievable for a given duration of the observations and it is usually underestimated. The corresponding correction factor to the Libbrecht formula for a frequency accuracy estimation is provided. We have also investigated the influence of the solar activity on the mode parameters soon after the solar activity minimum. There is a clearly visible increase of the radial p-mode power in the beginning of the new solar cycle while the mode frequency variations are within the corresponding error bars. 相似文献