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1.
The traditional least square estimation (LSE) method for orbit determination will not be optimal if the error of observational data does not obey the Gaussian distribution. In order to solve this problem, the least p-norm (Lp) estimation method is presented in this paper to deal with the non-Gaussian distribution cases. We show that a suitable selection of parameter p may guarantee a reasonable orbit determination result. The character of Lp estimation is analyzed. It is shown that the traditional Lp estimation method is not a robust method. And a stable Lp estimating based on data depth weighting is put forward to deal with the model error and outlier. In the orbit determination process, the outlier of observational data and coarse model error can be quantitatively described by their weights. The farther is the data from the data center, the smaller is the value of data depth and the smaller is the weighted value accordingly. The result of the new Lp method is stabler than that of the traditional Lp estimation and the breakdown point could be up to 1/2. In addition, the orbit parameter is adaptively estimated by residual analysis and matrix estimation method, and the estimation efficiency is enhanced. Finally, by taking the Space-based Space Surveillance System as an example and performing simulation experiments, we show that if there are system error or abnormal value in the observational data or system error in satellite dynamical model and space-based observation platform, LSE will not be optimal even though the observational data obeys the Gaussian distribution, and the orbit determination precision by the self-adaptive robust Lp estimation method is much better than that by the traditional LSE method. 相似文献
2.
It is an objective fact that there exists error in the satellite dynamic model and it will be transferred to satellite orbit determination algorithm, forming a part of the connotative model error. Mixed with the systematic error and random error of the measurements, they form the unitive model error and badly restrict the precision of the orbit determination. We deduce in detail the equations of orbit improvement for a system with dynamic model error, construct the parametric model for the explicit part of the model and nonparametric model for the error that can not be explicitly described. We also construct the partially linear orbit determination model, estimate and fit the model error using a two-stage estimation and a kernel function estimation, and finally make the corresponding compensation in the orbit determination. Beginning from the data depth theory, a data depth weight kernel estimator for model error is proposed for the sake of promoting the steadiness of model error estimation. Simulation experiments of SBSS are performed. The results show clearly that the model error is one of the most important effects that will influence the precision of the orbit determination. The kernel function method can effectively estimate the model error, with the window width as a major restrict parameter. A data depth-weight-kernel estimation, however, can improve largely the robustness of the kernel function and therefore improve the precision of orbit determination. 相似文献
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对于在轨运行的BDS (BeiDou Navigation Satellite System)卫星, 太阳光压是作用在卫星上主要的非引力摄动. 受多种因素的影响, 太阳光压摄动力难以精确建模, 是BDS卫星精密定轨和轨道预报过程中重要的误差来源. 由于ECOMC (Empirical CODE Orbit Model 1 and 2 Combined)模型兼顾了ECOM1 (Empirical CODE Orbit Model 1)和ECOM2 (Empirical CODE Orbit Model 2)模型的特点, 在模型中引入了较多的待估参数, 使得参数之间存在强相关性. 针对ECOMC模型的这一缺陷, 文中收集了2019年1月至2022年4月武汉大学分析中心提供的BDS-3卫星精密星历, 采用动力学轨道拟合方法得到了ECOMC模型的13个光压参数. 通过对该模型的光压参数进行时间序列分析, 分别给出了BDS-3 IGSO (Inclined Geosynchronous Orbit)和MEO (Medium Earth Orbit)卫星光压模型的参数选择策略. 并利用轨道拟合和轨道预报试验, 验证了光压模型参数选择策略的合理性. 结果表明, 采用改进型ECOMC模型进行BDS-3 IGSO和MEO卫星轨道拟合的效果最佳, 同时, 也能够提升BDS-3 IGSO和MEO卫星中长期轨道预报的精度. 相似文献
6.
将方差分量估计（VCE）方法应用于ERS－2卫星的精密定轨,用SLR和PRARE资料计算了1998年前3个月的23个长度为5天的弧段（除了调整轨道的时段外,相邻弧段有两天的重叠）,从观测值残差分析和重叠弧段比较两个方面,考察VCE方法对定轨计算的影响,并给出了各组观测值的平均验后均方差,对观测值残差的分析表明,使用VCE方法明显地改善了观测值的拟合程度,但从阿卑（Abbey)标准对观测值残差的检验结果来看,使用VCE方法不能消除轨道中由力学模型和几何模型误差引入的系统差,重叠弧段比较的结果表明：（1）使用VCE方法缩小了重叠弧段的平均距离差,并改善了一部分权段明显不合理的偏离,使最后得到的轨道具有更均匀的精度,（2）相比较而言,VCE方法使相邻弧段靠拢的趋势在轨道切向体现得较为明显,由各组观测值的平均验后方差可见,说单个标准点观测值而言,部分SLR台站的观测资料在定轨计算中占有比其他观测资料更重的地位,纵观全文,使用VCE后得到的观测值的平衡验后均方差来确定资料的双重将比使用均方差更为合理。 相似文献
7.
Zhang Fei-peng Huang Cheng Feng Chu-gang Dong Xiao-jun Liao Xin-hao 《Chinese Astronomy and Astrophysics》2001,25(4):641-489
Variance component estimation (VCE) is applied to precise orbit determination (POD) of the ERS-2 satellite. Twenty 5-day long arcs in the early three months in 1998 were calculated using the SLR and PRARE data. In the data the adjacent arcs overlap for two days except the intervals for orbit maneuver. The effect of VCE orbit determination on the calculation is investigated by an analysis of residuals and comparison of overlapping arcs, and the mean a posteriori standard deviation of each group of measured residuals is given. It is shown by the residuals analysis that the fitting of the measurements is significantly improved by VCD. However, according to Abbey criterion, VCD is not able to eliminate the systematic errors due to errors in the dynamic and geometric models. The results of the comparison of the overlapping arcs show that (1) VCE reduces the mean range deviation of overlapping arcs, especially where there are obviously unreasonable deviations, so that the orbit obtained has a more uniform precision; (2) By using VCE, adjacent arcs tend to close up and this is more apparent in the transverse direction. From the mean a posteriori standard error of each group of measurements, it can be seen that as far as the single normal point measurement is concerned, the data of some SLR stations are more important than other measurements in POD calculation. Generally speaking, determination of weighting by using VCE is more reasonable than by using initial standard deviation. 相似文献
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Starting with the status of the developments of oceanic altimetry satellites, the significance of orbit determination by using altimeter data is introduced. Then the error correction model of the altimeter data and the calculational method of the data of crossovers are analyzed. The modification quantities of the errors and the adopted model concerned in the files of the altimeter data from the aircraft JASON-1 are also introduced in detail. Finally, through the calculations of the simulated data and the data of actual measurements, the highest accuracies of the orbit determination reached by solely using the altimeter data and the data of crossovers are analyzed, respectively. And this work provides a valuable reference to the practical applications in future. 相似文献
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As a special approach to orbit determination for satellites with spaceborne GPS receivers, the kinematic Precise Orbit Determination (POD) is independent of any mechanical model (e.g., the Earth gravity ?eld, atmospheric drag, solar radiation pressure, etc.), and thus especially suitable for the orbit determination of Low Earth Orbiting (LEO)satellites perturbed strongly bythe atmosphere. In this paper, based on the space-borne dual-frequency GPS data, we study the kinematic POD, discuss the pre-processing of the data, and construct an algorithm of zero-difference kinematic POD. Using the observational data from GRACE (Gravity Recovery And Climate Experiment) satellites covering the whole month of February 2008, we verify the effectiveness and reliability of this algorithm. The results show that the kinematic POD may attain an accuracy of about 5 cm (with respect to satellite laser ranging data), which is at the same level as the dynamic and reduced-dynamic PODs 相似文献
10.
With the increased number of low Earth orbit (LEO) satellites equipped with Global Positioning System (GPS) receiver, the LEO based GPS slant total electron content (STEC) data play a more important role in ionospheric research due to better global coverage. The accuracy of LEO TEC is hardly evaluated by comparison with the independent TEC measurement simultaneously. We propose an approach based on the simulated data to verify the accuracy of TEC determination. The simulated data (i.e., the pseudorange and carrier phase observations) was generated based on the consideration of the effect of the ionosphere, the so-called differential code bias (DCB) and observational noise. The errors of carrier phase to code leveling process and DCB estimation are analyzed quantitatively. Also, the effect of observational noise, solar activity and LEO orbit altitude on the accuracy of TEC determination will be discussed in detail. The accuracy of TEC determination is relative to solar activity and LEO orbit altitude, the higher LEO orbit and lower F10.7 index, the higher accuracy of TEC determination. It is found by the first time that, with the amplification of the pseudorange noise, the accuracy of leveling process and TEC determination declines almost linearly. With the LEO missions in the near future, it is hoped that the GPS satellite DCBs estimated based on LEO observations would be better than those based on ground-based observations. 相似文献
11.
B. E. Schutz 《Celestial Mechanics and Dynamical Astronomy》1996,66(1):79-85
Modern observational techniques using ground-based and space-based instrumentation have enabled the measurement of the distance between the instrument and satellite to better than one centimeter. Such high precision instrumentation has fostered applications with centimeter-level requirements for satellite position knowledge. The determination of the satellite position to such accuracy requires a comparable modeling of the forces experienced by the satellite, especially when classical orbit determination methods are used. Geodetic satellites, such as Lageos, in conjunction with high precision ground-based laser ranging, have been used to improve for modeling of forces experienced by the satellite. Space-based techniques, such as Global Positioning System (GPS), offer alternatives, including kinematic techniques which require no modeling of the satellite forces, or only rudimentary models. This paper will describe the various techniques and illustrate the accuracies achieved with current satellites, such as TOPEX/POSEIDON, GPS/MET and the expectations for some future satellites. 相似文献
12.
LP估计在星载GPS运动学定轨中的应用及精度分析 总被引：2，自引：0，他引：2
为得到高精度的星载GPS运动学定轨,必须利用观测精度高的相位观测值,但是相位观测值预处理后,仍然存在残余小周跳．在残差服从正态分布情况下LS法是最佳参数解算方法,但该方法不能解决资料的系统误差消除问题,LP估计是处理资料残差分布含有系统误差的有效方法之一．基于LS、LP方法的有效条件和GPS数据预处理的特性,将LP估计方法引入星载GPS运动学定轨数据处理中,以CHAMP卫星资料为例,研究了LP估计在星载GPS运动学定轨中的应用及其精度分析．实践表明:在处理含有残余小周跳的相位观测值时,LP估计比LS更有效,提高了星载GPS运动学定轨精度,但随着残余周跳的进一步修复,LP估计相对于LS估计的优越性越来越弱,在资料完全没有系统误差,残差服从正态分布的情况下,LP估计不能很好地体现其优越性,精度反而低于LS估计． 相似文献
13.
From the point of view of the non-parametric statistics, a general estimation method of the accuracy and con?dence interval of preliminary orbit determination is proposed for the occasion without any other information but observational data. Based on the bootstrap method, the estimation relies only on the observational data and does not require the precise orbit determination as a reference, or the assumption of normal distribution of observational errors. Numerical experiments show that this method is very simple in implementa- tion, and may serve as an easy accuracy evaluation for the preliminary orbit determination and for the follow-up employments. 相似文献
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区域北斗星基增强系统提供等效钟差改正数统一修正星历和钟差误差。随着系统的建设发展,新一代北斗星基增强系统将区分星历和钟差误差改正信息,以提高差分改正精度。由于北斗卫星混合星座设计及区域监测网的局限,星历和钟差误差的高精度分离计算面临着新的挑战。对北斗星基增强系统的星历和钟差改正算法进行了研究,分别采用动力学和运动学模式计算了卫星星历和钟差改正数,并基于北斗实测数据,对两种处理模式的差分改正精度进行了对比研究。试验结果表明,采用动力学和运动学差分方法,得到的双频伪距实时定位精度分别为1.76m和1.78m,定位精度与WAAS及EGNOS相当。利用运动学和动力学差分改正数后均可得到分米级的精密单点定位(precise point position,PPP)结果,其中采用动力学广域差分改正数,收敛后定位精度可达到15cm;采用运动学广域差分改正数,收敛后定位精度可达45cm。 相似文献
15.
《Chinese Astronomy and Astrophysics》2023,47(1):204-220
In view of the limitation of ground-based Tracking Telemetry and Command (TT&C) system in covering the geostationary satellite in space and time, the method of determining the orbit of the geostationary satellite by the LEO (Low Earth Orbit) multi-satellites network with small orbit inclination was proposed. According to the space environment and optical viewing conditions, the simulation data were screened to simulate the real observation scene. The precise orbit determination (POD) of geostationary satellite was calculated by using the optical angle measurement data and the numerical method. By comparing with the reference orbit, under the condition of platform’s orbit accuracy of 5 m, measurement accuracy of 5-arcsecond, and 12 hours of observation, the POD accuracy of geostationary satellite by two LEO satellites can reach the order of kilometers, while the POD accuracy by four LEO satellites can reach the order of 100 meters. Therefore, the POD accuracy has been greatly improved with the increase of the number of LEO satellites. 相似文献
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针对地基卫星测控系统(Tracking Telemetry and Command, TT&C)系统对地球静止轨道(Geostation-\lk ary Earth Orbit, GEO)卫星在空间和时间覆盖上的局限性, 提出小倾角低地球轨道(Low Earth Orbit, LEO)多星组网天基平台对GEO卫星进行跟踪定轨的方法. 根据空间环境和光学可视条件对仿真数据进行筛选以模拟真实的观测场景, 利用光学测角数据, 使用数值方法对GEO卫星的轨道进行确定. 结果与参考轨道进行重叠对比, 在平台轨道精度5 m、测量精度5rq\rq、 定轨弧长12 h的情况下, 两颗LEO卫星对GEO卫星进行跟踪定轨的精度可达到千米量级, 4颗LEO卫星对GEO目标进行跟踪定轨的精度可达到百米量级. 随着LEO组网卫星数量的增加, 定轨精度得到了较大的提高. 相似文献
17.
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
18.
Modeling the effects of atmospheric drag is one of the more important problems associated with the determination of the orbit of a near-earth satellite. Errors in the drag model can lead to significant errors in the determination and prediction of the satellite motion. The uncertainty in the drag acceleration can be attributed to three separate effects: (a) errors in the atmospheric density model, (b) errors in the ballistic coefficient, and (c) errors in the satellite relative velocity. In a number of contemporary satellite missions, the requirements for performing the orbit determination and predictions in near real-time has placed an emphasis on density model computation time as well as the model accuracy. In this investigation, a comparison is made of three contemporary atmospheric density models which are candidates for meeting the current orbit computation requirements. The models considered are the analytic Jacchia-Roberts model, the modified Harris-Priester model, and the USSR Cosmos satellite derived density model. The computational characteristics of each of the models are compared and a modification to the modified Harris-Priester model is proposed which improves its ability to represent the diurnal variation in the atmospheric density.This investigation was supported by the NASA Goddard Spaceflight Center under contract NAS5-20946 and Contract NSG 5154. 相似文献
19.
Gas-surface interactions and satellite drag coefficients 总被引：1，自引：0，他引：1
Information on gas-surface interactions in orbit has accumulated during the past 35 years. The important role played by atomic oxygen adsorbed on satellite surfaces has been revealed by the analysis of data from orbiting mass spectrometers and pressure gauges. Data from satellites of special design have yielded information on the energy accommodation and angular distributions of molecules reemitted from satellite surfaces. Consequently, it is now possible to calculate satellite drag coefficients from basic physical principles, utilizing parameters of gas-surface interactions measured in orbit. The results of such calculations are given. They show the drag coefficients of four satellites of different compact shapes in low-earth orbit with perigee altitudes in the range from about 150 to 300 km, where energy accommodation coefficients and diffuse angular distributions have been measured. The calculations are based on Sentman's analysis of drag forces in free-molecular flow. His model incorporates the random thermal motion of the incident molecules, and assumes that all molecules are diffusely reemitted The uncertainty caused by the assumption of diffuse reemission is estimated by using Schamberg's model of gas-surface interaction, which can take into account a quasi-specular component of the reemission. Such a quasi-specular component is likely to become more important at higher altitudes as the amount of adsorbed atomic oxygen decreases. A method of deducing accommodation coefficients and angular distributions at higher altitudes by comparing the simultaneous orbital decay of satellites of different shapes at a number of altitudes is suggested. The purpose is to improve thermospheric measurements and models, which are significantly affected by the choice of drag coefficients. 相似文献
20.
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