圆轨道数值积分的稳定性

本文讨论了用经典的Cowell方法数值积分Kepler圆轨道时的稳定性问题,对各阶PE、PECE、CE 算法给出了稳定区域的边界步长值h_m。与其他作者的计算相比,表明本文采用的处理方法比较恰当,结果更为精确。     

太阳同步卫星的控制现状及发展趋势

在介绍太阳同步轨道相关知识的基础上,着重分析了该轨道的高度因素,给出了当前在轨太阳同步卫星轨道高度的上下限,介绍了几种典型的低轨道太阳同步卫星,同时给出了太阳同步卫星轨道控制方法的发展状况及趋势,最后综述了当前国内外太阳同步轨道的轨控模式与维持策略。     

稳定化方法与后稳定化方法的比较

对BaumgaLrte的稳定化和Chin的后稳定化进行了详尽讨论与数值比较．用经典数值方法并结合这两种稳定化方式都能提高数值精度和改善数值稳定性．在最佳稳定参数下稳定化精度一般不等价于后稳定化．两者精度优劣并无常定．考虑到Baumgarte的稳定化使得数值积分的右函数更复杂和增加计算耗费,尤其是存在稳定参数最佳选取的麻烦,故推荐后稳定化投入实算．但值得注意的是用后稳定化与没有经过稳定化处理的经典积分器来比不宜扩大积分步长．     

日像仪的电磁干扰分析

讨论了日像仪的干扰容限，列出了干扰源分布，估算出干扰测试仪灵敏度。计算了同步卫星干扰及干扰时间预测，也分析了中低轨道卫星干扰问题。对移动通信基站产生的干扰作了传播分析、计算，对脉冲雷达干扰作了谱分析及保守计算。     

天文历表的逼近方法和计算机历书

本文讨论了用多项式逼近天文历表的方法.对于等间距列表数值,给出了计算切比雪夫系数以及计算最佳拟合式的算法,并介绍一组编算计算机历书的标准程序.     

初轨计算精度的bootstrap估计

从非参数统计角度,在仅有观测资料而没有其它信息的情况下,分别给出了初轨计算的精度和置信区间的估计方法.该方法基于bootstrap方法,仅依赖于观测资料,不需要精密定轨结果作为参考,也无需假设观测资料误差呈正态分布,并且对各种初轨计算方法均适用.数值计算结果表明该方法应用简便,可作为初轨的评估和后续应用的重要参考.     

SGP4/SDP4模型预报可靠性分析

以激光测距资料精密定轨结果为参考轨道,分析了两种典型版本SGP4/SDP4模型对低、中、高轨道卫星预报误差的放大规律,当预报超过一定的圈数后误差成指数增长.数值试验结果表明:对低、中、高轨卫星预报误差无显著放大圈数分别是(h≤300 km),40;(300 km≤h≤1 200 km),150;(1 200 km≤h≤10 000 km),300;半同步卫星(19 000km≤h≤22 000 km),55;同步卫星(33 000 km≤h≤38 000 km),10.并图示出参考卫星轨道预报误差的放大规律,供工程中利用双行根数和SGP4/SDP4模型作轨道预报时参考.     

区域分解方法在快速旋转行星流体动力学并行计算中的应用

基于区域分解思想建立了一种快速旋转行星流体动力学大规模二维数值模拟并行计算方法,并在PC-Cluster型并行计算机上进行了各种网格的数值模拟,结果表明:在一定的CPU数目范围内,该方法在PC-Cluster型并行计算机上的计算速度基本上与采用的CPU数目成线性正比关系.     

大口径射电望远镜主面误差分析与修正

建立了40 m口径射电望远镜天线结构有限元模型,依据模型分析结果,对40 m口径射电望远镜天线主面误差进行了分析和数值计算;从误差修正的角度,分别对主面误差的最佳拟合修正、安装角预调的工作仰角综合修正进行了分析与数值计算．误差修正后的计算结果表明,主面精度得到了大幅度的提高．分析结果为该望远镜天线的实际建造提供了参考．     

一种适用于大偏心率轨道密集星历精密计算的快速处理方法

空间目标探测和编目是航天器安全的重要课题, 空间目标数量巨大, 造成轨道计算的工作量十分繁重. 分析方法虽然计算速度快, 却不能适应高精度观测资料的处理工作, 因而数值方法将成为目标轨道计算的重要方法. 空间目标编目工作普遍涉及密集星历的产生和计算问题, 针对这一问题的大偏心率轨道数值计算目前尚未形成兼具计算精度和计算效率的有效技术手段, 难以满足编目工作的处理要求. 在此背景下, 提出一种适用于大偏心率轨道密集星历精密计算的快速处理方法, 并通过数值实验对模型参数进行优选, 最后通过计算实例证实了该计算方案的优越性.     

同步卫星短弧定轨

同步卫星受到摄动力的影响,它的实际轨道有一点漂移．卫星需要不断的调轨调姿,以保证其正常运行．为了研究卫星在几小时,甚至更短的时间内的轨迹情况,采用短弧段定轨法．用动力学方法进行短弧定轨,分别研究1小时和15分钟定轨并进行比较,目的是为了在同步轨道卫星变轨后,能尽快地为卫星提供精密的预报轨道．此外,在系列短弧定轨后,得到精密轨道系列,为研究轨道变化的力学因素及研究短弧中卫星转发器时延变化规律等提供依据．     

星载GPS精密测轨研究及应用

星载ＧＰＳ定轨系统由于其全天侯、价格低、不受卫星高度的影响可达到米级、分米级乃至厘米级的测轨精度等特点已成为低轨道卫星精密定轨的要求,概述了星载ＧＰＳ系统的组成和定轨原理,给出了星载ＧＰＳ测轨的几种主要方法和数学模型,同时根据ＴＯＰＥＸ卫星星载ＧＰＳ实测数据分析了各种定轨方法的测轨精度以及影响定轨精度的各种因素。     

Simultaneous ground-satellite observations of Pi 2 magnetic pulsations and their high frequency enhancement

Pi 2 magnetic pulsations are a frequent occurrence at the earth's surface and have been shown to be clearly correlated with substorm expansion onset. These pulsations are also observed in space at synchronous orbit at the same time as they are seen on the ground at the satellite conjugate point. In this brief report we describe three days in 1969 on which Pi 2 magnetic pulsations were simultaneously observed at the synchronous satellite ATS 1 and at Tungsten, N.W.T., Canada, near the foot of the ATS 1 magnetic field line. These Pi 2 bursts all exhibit the characteristic waveform and frequency, as well as an ～0.3 Hz enhancement, at both locations. This high frequency enhancement appears to be an integral part of Pi 2 bursts both on the surface and at synchronous orbit and should be considered in the development of models of generation mechanisms.     

光压摄动计算中地影间断的处理

人卫精密定轨中受摄星历（或称精密星历,即状态转移）,可由分析解或数值解提供,相应的定轨方法亦有分析法定轨与数值法定轨之称。对于后者,在一般情况下,现有的常微分方程数值解法（或称积分器）已能满足精度要求,除长弧定轨外,有一定问题是值得注意的,即地影“间断”问题的处理,这关系到如何在保证星历精度的前提下提高计算效率的问题。本文针对这一问题,给出了相应的改进算法,并通过数值验证表明算法的有效性。     

A new family of multistep numerical integration methods based on Hermite interpolation

In this paper, a new family of explicit and implicit multistep methods is presented both for the error-controlled and uncontrolled modes. The main concept is to replace the Newton interpolation with the Hermite interpolation, where the Hermite polynomial is fitted to the function values and its derivatives. This idea is very useful in the numerical solution of problems (e.g., orbit propagation problem) where higher-order derivatives can easily be computed. In addition to the theoretical concept, the stability regions of the proposed methods are determined. The new methods are more stable than the well-known multistep numerical integrators (i.e., Adams–Bashforth and Adams–Bashforth–Moulton) in the explicit, implicit, and predictor–corrector forms. Using the second-order derivatives gives smaller error constants in the proposed method. The new integrators are numerically tested for a few examples, and the solutions are compared with those of the well-known multistep methods. Moreover, the CPU time and absolute integration error are compared in the satellite orbit propagation problem using various integration methods. The CHAMP mission, i.e., a German small-satellite mission for geoscientific and atmospheric research and applications, is considered as a case study for comparing the achievable accuracy of the proposed method with the existing method for solving the two-body problem.     

Variational and symplectic integrators for satellite relative orbit propagation including drag

Orbit propagation algorithms for satellite relative motion relying on Runge–Kutta integrators are non-symplectic—a situation that leads to incorrect global behavior and degraded accuracy. Thus, attempts have been made to apply symplectic methods to integrate satellite relative motion. However, so far all these symplectic propagation schemes have not taken into account the effect of atmospheric drag. In this paper, drag-generalized symplectic and variational algorithms for satellite relative orbit propagation are developed in different reference frames, and numerical simulations with and without the effect of atmospheric drag are presented. It is also shown that high-order versions of the newly-developed variational and symplectic propagators are more accurate and are significantly faster than Runge–Kutta-based integrators, even in the presence of atmospheric drag.     

Synchronous spin-orbital resonance locking of large planetary satellites

A numerical investigation of the chaotic rotation of large planetary satellites before their synchronous spin-orbital resonance locking with regard to tidal friction is carried out. The rotational dynamics of seven large satellites greater than 1000 km in diameter and with known inertial parameters (Io, Europa, Ganymede, Callisto (J1–J4), Tethys (S3), Iapetus (S8), and Ariel (U1)) in the epoch of synchronous resonance locking is modeled. All of these satellites have a small dynamic asymmetry. The planar case is considered in which the satellite’s axis of rotation is orthogonal to the plane of orbit. The satellites possessing an initial rapid rotation pass through various resonant states during the tidal evolution. Here, the probability of their locking into these states exists. The numerical experiments presented in this paper have shown that, with a rather high arbitrariness in the choice of initial states, the satellites during the course of the tidal evolution of their rotational motion have passed without interruption through the regions of the 5: 2, 2: 1, and 3: 2 resonances in the phase space and are locked into the 1: 1 resonance. The estimate for the tidal deceleration time is obtained both theoretically and on the numerical experimental basis.     

Approximate analytic method for high-apogee twelve-hour orbits of artificial Earth’s satellites

We propose an approach to the study of the evolution of high-apogee twelve-hour orbits of artificial Earth’s satellites. We describe parameters of the motion model used for the artificial Earth’s satellite such that the principal gravitational perturbations of the Moon and Sun, nonsphericity of the Earth, and perturbations from the light pressure force are approximately taken into account. To solve the system of averaged equations describing the evolution of the orbit parameters of an artificial satellite, we use both numeric and analytic methods. To select initial parameters of the twelve-hour orbit, we assume that the path of the satellite along the surface of the Earth is stable. Results obtained by the analytic method and by the numerical integration of the evolving system are compared. For intervals of several years, we obtain estimates of oscillation periods and amplitudes for orbital elements. To verify the results and estimate the precision of the method, we use the numerical integration of rigorous (not averaged) equations of motion of the artificial satellite: they take into account forces acting on the satellite substantially more completely and precisely. The described method can be applied not only to the investigation of orbit evolutions of artificial satellites of the Earth; it can be applied to the investigation of the orbit evolution for other planets of the Solar system provided that the corresponding research problem will arise in the future and the considered special class of resonance orbits of satellites will be used for that purpose.     

一种同步卫星授时方法

本文简要分析了当前采用的各种时刻比对方法和技术，强调指出了静止卫星共视法在当前我国时刻比对工作中的实际应用价值，并对亚星一号进行了动力学定轨及时刻比对实验．实算结果表明：在现有的观测精度下，对亚星一号进行微分轨道改进后，可使共视法比对的事后处理精度优于１μｓ，其预报精度在１—２天内可达１μｓ，在一个星期内也只有几个微秒．