From Astrometry to Celestial Mechanics: Orbit Determination with Very Short Arcs   总被引：1，自引：1，他引：0  

Andrea Milani  Zoran Knežević 《Celestial Mechanics and Dynamical Astronomy》2005,92(1-3):1-18

Contemporary surveys provide a huge number of detections of small solar system bodies, mostly asteroids. Typically, the reported astrometry is not enough to compute an orbit and/or perform an identification with an already discovered object. The classical methods for preliminary orbit determination fail in such cases: a new approach is necessary. When the observations are not enough to compute an orbit we represent the data with an attributable (two angles and their time derivatives). The undetermined variables range and range rate span an admissible region of solar system orbits, which can be sampled by a set of Virtual Asteroids (VAs) selected by an optimal triangulation. The attributable results from a fit and has an uncertainty represented by a covariance matrix, thus the predictions of future observations can be described by a quasi-product structure (admissible region times confidence ellipsoid), which can be approximated by a triangulation with each node surrounded by a confidence ellipsoid. The problem of identifying two independent short arcs of observations has been solved. For each VA in the admissible region of the first arc we consider prediction at the time of the second arc and the corresponding covariance matrix, and we compare them with the attributable of the second arc with its own covariance. By using the penalty (increase in the sum of squares, as in the algorithms for identification) we select the VAs which can fit together both arcs and compute a preliminary orbit. Even two attributables may not be enough to compute an orbit with a convergent differential corrections algorithm. The preliminary orbits are used as first guess for constrained differential corrections, providing solutions along the Line Of Variations (LOV) which can be used as second generation VAs to further predict the observations at the time of a third arc. In general the identification with a third arc will ensure a least squares orbit, with uncertainty described by the covariance matrix.  相似文献   

初轨计算的参考矢量法   总被引：3，自引：0，他引：3  

贾沛璋  吴连大 《天文学报》1997,38(4):353-358

本文从最优估计角度研究短弧资料定初轨问题，提出一种最小二乘估计算法，同时提出一种符合实用的参考矢量法．仿真结果显示，参考矢量法克服了现有初轨算法所承受病态影响，把定轨精度提高到接近最佳水平．  相似文献   

A new procedure for the solution of the classical problem of minimal orbit determination from three lines of sight   总被引：1，自引：0，他引：1  

R. H. Gooding 《Celestial Mechanics and Dynamical Astronomy》1996,66(4):387-423

A new method has been developed for obtaining multiple solutions of the classical angles-only initial-orbit-determination problem. The method operates by a higher-order Newton correction of the assumed values for two of the unknown ranges, with the author's universal Lambert algorithm at the heart of the procedure. The observations are permitted to span several revolutions when the orbit is elliptic, and the method is free of artificial singularities in the configuration of observers and sight-lines; thus it has been successfully used with some test problems that would not be solvable by existing methods.Former affiliation: Royal Aerospace Establishment, Farnborough  相似文献   

J2 Invariant Relative Orbits for Spacecraft Formations   总被引：1，自引：0，他引：1  

Hanspeter Schaub  Kyle T. Alfriend 《Celestial Mechanics and Dynamical Astronomy》2001,79(2):77-95

An analytic method is presented to establish J ₂ invariant relative orbits. Working with mean orbit elements, the secular drift of the longitude of the ascending node and the sum of the argument of perigee and mean anomaly are set equal between two neighboring orbits. By having both orbits drift at equal angular rates on the average, they will not separate over time due to the J₂ influence. Two first order conditions are established between the differences in momenta elements (semi-major axis, eccentricity and inclination angle) that guarantee that the drift rates of two neighboring orbits are equal on the average. Differences in the longitude of the ascending node, argument of perigee and initial mean anomaly can be set at will, as long as they are setup in mean element space. For near polar orbits, enforcing both momenta element constraints may result in impractically large relative orbits. It this case it is shown that dropping the equal ascending node rate requirement still avoids considerable relative orbit drift and provides substantial fuel savings.This revised version was published online in October 2005 with corrections to the Cover Date.  相似文献   

万有引力和向心力在行星公转和自转中的作用机制     

刘序俨 《大地测量与地球动力学》1995,(4)

论述了万有引力和向心力在行星公转和自转中的作用机制，特别指出地表任一质点随同地球自转所作的圆周运动中向心力是较之离心力更为实在的外在动因，并认为该动因是由地球引力所提供的。最后对向心力在地壳形变和地球动力学中的作用进行了讨论。  相似文献   

GPS精密星历的外推精度分析   总被引：1，自引：0，他引：1  

常志巧  郝金明  张成军 《测绘工程》2006,15(2):27-29,39

列出了轨道拟合和轨道外推所用的摄动力模型,讨论了轨道拟合和轨道积分的过程。利用轨道拟合的方法拟合出高精度的初始轨道参数,在此基础上外推7天的轨道,将结果与IGS提供的最终星历比较,得出GPS轨道的外推精度:每颗卫星都是切向误差最显著,径向和法向的误差不明显;星蚀卫星的轨道外推精度明显低于一般卫星;问题卫星的轨道外推误差特别大。  相似文献   

导航卫星的历书参数及其拟合算法   总被引：8，自引：0，他引：8  

崔先强  焦文海  秦显平 《测绘科学技术学报》2006,23(1):23-25

介绍了GPS卫星的历书参数,分析了它们在GEO、IGSO和MEO卫星应用中存在的问题.提出了一种改进的历书参数及其估计算法,并分别用于GEO、IGSO和MEO卫星.计算结果表明,改进的历书参数及其估计算法能同时适用于GEO、IGSO和MEO卫星,且历书参数的拟合精度损失满足卫星快速捕获的要求.  相似文献   

Evaluation of CHAMP satellite orbit with SLR measurements   总被引：1，自引：0，他引：1  

QIN Xianping YANG Yuanxi 《地球空间信息科学学报》2005,8(3):209-213

The technique of Evaluating CHAMP satellite orbit with SLR measurements iS presented. As an independent evaluation of the orbit solution, SLR data observed from January 1 to 16, 2002 are processed to compute the residuals after fixing the GFZ＇s post science orbits solutions. The SLR residuals are computed as the differences of the SLR measurements minus the corresponding distances between the SLR station and the GPS-derived orbit positions. On the basis of the SLR residuals analysis, it is found that the accuracy of GFZ＇ s post science orbits is better than 10 cm and that there is no systematic error in GFZ＇s post science orbits.  相似文献   

The Effect of GPS Ephemeris on the Accuracy of Precise Orbit Determination of LEO Satellite-borne GPS     

PENG Dong-ju  WU Bin 《Chinese Astronomy and Astrophysics》2009

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   

地震监测雷达卫星系统参数的设计     

谌华  单新建  陈国浒  张景发  程滔 《大地测量与地球动力学》2005,25(2):98-102

初步设计了地震监测雷达卫星的轨道参数,讨论了单颗雷达卫星的参数,以及3颗或4颗卫星组成卫星星座时重访周期的变化情况。  相似文献