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月球卫星轨道力学综述 总被引:5,自引:0,他引:5
月球探测器的运动通常可分为3个阶段,这3个阶段分别对应3种不同类型的轨道:近地停泊轨道、向月飞行的过渡轨道与环月飞行的月球卫星轨道。近地停泊轨道实为一种地球卫星轨道;过渡轨道则涉及不同的过渡方式(大推力或小推力等);环月飞行的月球卫星轨道则与地球卫星轨道有很多不同之处,它决不是地球卫星轨道的简单克隆。针对这一点,全面阐述月球卫星的轨道力学问题,特别是环月飞行中的一些热点问题,如轨道摄动解的构造、近月点高度的下降及其涉及的卫星轨道寿命、各种特殊卫星(如太阳同步卫星和冻结轨道卫星等)的轨道特征、月球卫星定轨等。 相似文献
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卫星轨道预报的一种分析方法 总被引:5,自引:0,他引:5
人造地球卫星的轨道预报是空间环境监测和实时跟踪测量中一个重要环节,由于监测对象众多,要求精度也不太高,通常采用分析法预报.在已有分析法得到t时刻平均根数的基础上给出一种轨道预报方法,由t时刻的平均根数给出该时刻卫星的位置和速度,在此基础上将地球非球形引力摄动的周期项直接用卫星直角坐标的位置和速度分量表示,这样可以避免在计算轨道根数变化的周期项时出现的奇点问题,从而对根数的选择无特殊要求,可适用于各种轨道,简化预报程序和相应的软件,提高预报效率。 相似文献
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从理论上探讨圆周运动天体轨道半径的相对论效应,并应用于行星际飞船与人造地球卫星的情形。结果表明,在这两种情形中,均存在着可观测的效应。 相似文献
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分析表明,卫星轨道偏差对预报的影响主要表现在M和Ω这两个轨道根数上。本给出了M、Ω的修正公式,并结合LAGEOS测距数据,对卫星的短期预报进行修正,取得了满意的结果。 相似文献
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制约卫星轨道寿命的另一种机制(续) 总被引:2,自引:0,他引:2
对于制约低轨人造地球卫星轨道寿命的耗散机制,人们已有足够的重视,但在深空探测中,另一种制约低轨卫星轨道寿命的引力机制同样应予重视,前文讨论了高轨卫星的情况,在第三体引力作用下,有可能导致卫星轨道偏心率产生变幅较大的长周期变化。特别是极轨卫星,其轨道偏心率在一定的时间内可增大到使其近星距rp=a(1-e)≈Re(Re是中心天体的赤道半径),从而落到中心天体上,结束其轨道寿命,目前对低轨卫星作了详尽的理论分析,研究表明,与高轨卫星有类似结果,但其力学机制却不相同,低轨卫星的轨道寿命与第三体引力无关。它取决于中心天体非球形引力位中的扁率项(即J2项)与其他带谐项之间的相对大小,这不仅是一个纯理论结果,也有实际背景,在太阳系中慢自传天体(月球和金星等)的低轨卫星就存在这一问题,还给出了有关判据,并以计算实例作了验证。 相似文献
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对于改进的Encke方法,选择适当的参考轨道是一个关键.然而,对于人造地球卫星长弧轨道计算,目前所给出的几种参考轨道均需要逐段校正,这将给定轨问题带来附加的复杂性.本文将仔细探讨如何选择参考轨道和减少校正次数. 相似文献
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针对国内气象部门的要求,本文就某一特定地域对地球低轨道卫星进行轨道计算,使得地面测点能维持在该区域较长时间.计算结果表明该轨道可以使得无线电掩星的地面测点维持在辐射半径为100km之内的区域达130天左右。这基本满足了利用GPS无线电掩星技术对局部地域大气进行监测研究的要求。 相似文献
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轨道偏心率的变化极其重要,它是制约各类(不同高度)空间飞行体轨道寿命的关键因素之一.对于地球低轨卫星,主要受大气耗散作用的影响,而对环月(或环火星)低轨卫星,主要受非球形引力位中奇次带谐项的影响,会出现变幅较大的长周期变化,从而导致近星点高度hp在一段时间内有明显的下降趋势.对大偏心率轨道和高轨道,第三体的引力作用也会使e出现变幅较大的长周期变化,近星点高度hp也会有明显下降的现象,这都会影响卫星的轨道寿命,但这一动力学机制与大气耗散机制和非球形引力机制都不相同.即对轨道偏心率的变化特征及其对轨道寿命的影响作一综述. 相似文献
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Richard L. Branham Jr. 《Celestial Mechanics and Dynamical Astronomy》2005,93(1-4):53-68
Laplace’s method is a standard for the calculation of a preliminary orbit. Certain modifications, briefly summarized, enhance
its efficacy. At least one differential correction is recommended, and sometimes becomes essential, to increase the accuracy
of the computed orbital elements. Difficult problems, lack of convergence of the differential corrections, for example, can
be handled by total least squares or ridge regression. The differential corrections represent more than just getting better
agreement with the observations, but a means by which a satisfactory orbit can be calculated. The method is applied to three
examples of differing difficulty: to calculate a preliminary orbit of Comet 122/P de Vico from 59 observations made during
five days in 1995; a more difficult calculation of a possible new object with a poor distribution of observations; Herget’s
method fails for this example; and finally a really difficult object, the Amor type minor planet 1982 DV (3288 Seleucus).
For this last object use of L1 regression becomes essential to calculate a preliminary orbit. For this orbit Laplace’s method compares favorably with Gauss’s. 相似文献
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论述的短弧定轨,是指在无先验信息情况下又避开多变元迭代的初轨计算方法,它需要相应的动力学问题有一能反映短弧内达到一定精度的近似分析解.探测器进入月球引力作用范围后接近月球时可以处理成相对月球的受摄二体问题,而在地球附近,则可处理成相对地球的受摄二体问题,但在整个过渡段的力模型只能处理成一个受摄的限制性三体问题.而限制性三体问题无分析解,即使在月球引力作用范围外,对于大推力脉冲式的过渡方式,相对地球的变化椭圆轨道的偏心率很大(超过Laplace极限),在考虑月球引力摄动时亦无法构造摄动分析解.就此问题,考虑在地球非球形引力(只包含J2项)和月球引力共同作用下,构造了探测器飞抵月球过渡轨道段的时间幂级数解,在此基础上给出一种受摄二体问题意义下的初轨计算方法,经数值验证,定轨方法有效,可供地面测控系统参考. 相似文献
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The ASTROD-GW (ASTROD [Astrodynamical Space Test of Relativity Using Optical Devices] Optimized for Gravitation Wave Detection), the mission of the laser astrodynamical gravitational wave detection, is the scheme of optimality of the gravitational wave detection on which the ASTROD is concentrated. Its spacecraft orbits form a triangular array close to an equilateral triangle in the vicinity of the solar-terrestrial Lagrangian points L3, L4 and L5. The length of the interference arm is about 2.6 × 108 km and the detectable wavelength of the gravitational wave is 52 times larger than that detected by the LISA (Laser Interferometer Space Antenna). In this article, the design and optimization method of the ASTROD-GW orbit are summarized. After the orbit is optimized, the variation in the arm length difference (which can be called the interference difference in laser interferometry) within 10 years is in the order of magnitude of 10−4 AU. The Doppler velocities in the three arm length directions are smaller than 4 m/s, and all of them are less than that required by the LISA. Therefore the laser ranging techniques developed by the LISA can be applied to the ASTROD-GW. 相似文献
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The orbit of 1976 AA is determined and its evolution studied over an interval of seven centuries into both the past and future. 相似文献
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激光天文动力学引力波探测任务ASTROD-GW(ASTROD[AstrodynamicalSpace Test of Relativity Using Optical Devices Optimized for Gravitation WaveDetection)是ASTROD专注于探测引力波的优化方案,其航天器轨道在日地拉格朗日点L_3、L_4、L_5附近,构成一个接近等边的三角形阵列,干涉臂长约为2.6×10~8 km,其可探测的引力波波长可达LISA(Laser Interferometer Space Antenna)的52倍.文中综述ASTROD-GW轨道的设计和优化方法.轨道经优化后,其臂长差(在激光干涉测量中可称为干涉差)10 yr内的变化为10~(-4) AU量级、3个臂长方向的多普勒速度小于4 m/s,均小于LISA的要求,因此LISA发展的激光测距技术可用于ASTROD-GW. 相似文献
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Abstract— Because the path of the Murchison meteorite fortuitously intersected the Earth's path at an angle of only a few degrees, the visual observations establish the entry velocity to be within 2 km/s of 13 km/s and determine the nature of its orbit with a precision quite unusual for visually sighted falls. 相似文献
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Using statistical orbital ranging, we systematically study the orbit computation problem for transneptunian objects (TNOs). We have automated orbit computation for large numbers of objects, and, more importantly, we are able to obtain orbits even for the most sparsely observed objects (observational arcs of a few days). For such objects, the resulting orbit distributions include a large number of high-eccentricity orbits, in which TNOs can be perturbed by close encounters with Neptune. The stability of bodies on the computed orbits has therefore been ascertained by performing a study of close encounters with the major planets. We classify TNO orbit distributions statistically, and we study the evolution of their ephemeris uncertainties. We find that the orbital element distributions for the most numerous single-apparition TNOs do not support the existence of a postulated sharp edge to the belt beyond 50 AU. The technique of statistical ranging provides ephemeris predictions more generally than previously possible also for poorly observed TNOs. 相似文献
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L. Kahl Kristensen 《Astronomische Nachrichten》1995,316(4):261-266
An elliptic orbit is determined from two short-arc pairs of observations at different oppositions by the angular momentum integral. Other methods for initial orbit determination than the classical do exist. 相似文献