拟合后剩余残差的统计检验与待估参数的选择

在空间技术的实际资料处理中,经常遇到不同待估参数组合解算的ＲＭＳ水平大致相当而估值结果相差甚远的情况．本文提出采用残差统计检验的方法,结合ＲＭＳ的大小,来判断精密定轨和参数解算的好坏．将拟合后的剩余残差序列看作一个随机变量样本,并假设其满足正态分布,采用高阶矩和皮尔逊χ２ 统计量来度量残差序列偏离正态分布的程度．根据统计检验的结果,提出选择合适的待估参数的标准     

多种资料综合处理的精度分析和相对权因子

在统计轨道理论的框架下分析多种技术资料的综合处理方法的精度．提出除了拟合剩余残差的ＲＭＳ外,皮尔逊（Ｐｅａｒｓｏｎ） χ２ 统计量和高阶矩也应作为判断解算好坏的重要指标．初步探讨了利用这些统计量评价不同技术间的相对权因子给定问题．作为对系统差来源的初步探索,利用考察协方差分析理论分析了考察参数误差对解算的影响,讨论了考察协方差与相对权因子的关系     

A Computation on Velocity Field of the Post-flare Loop System of August 17, 1989

1　ＯｂｓｅｒｖａｔｉｏｎａｌｖｅｌｏｃｉｔｙｆｉｅｌｄＷｅａｎａｌｙｓｅＨβｓｐｅｃｔｒａｏｂｔａｉｎｅｄａｔＹｕｎｎａｎＯｂｓｅｒｖａｔｏｒｙｗｉｔｈｔｈｅｔｗｏ ｄｉｍｅｎｓｉｏｎＭｕｌｔｉ Ｗａｖｅ ｂａｎｄＳｐｅｃｔｒａ ＳｐｅｃｔｒｏＨｅｌｉｏＧｒａｐｈ (ＭＷ ＳＳＨＧ) (ＸｕａｎａｎｄＬｉｎ 1 993) .ＴｈｅＰＦＬｓａｐｐｅａｒｅｄａｔ0 1 :0 4ＵＴｏｆＡｕｇｕｓｔ 1 7,1 989ｏｎｔｈｅｗｅｓｔｅｒｎｓｏｌａｒｌｉｍｂａｂｏｖｅｔｈｅｌａｒｇｅａｃｔｉｖｅｒｅｇｉｏｎ (ＡＲ 5 6 2 9,Ｓ1 5°;Ｗ 1 …     

PUBLICATIONS OF THE YUNNAN OBSERVATORY 2001 CONTENTS

ＳｔａｒＰｈｙｓｉｃｓＰｒｏｇｒｅｓｓｉｎｔｈｅＳｔｕｄｙｏｆＡｂｕｎｄａｎｃｅｓｏｆＨｅａｖｙＥｌｅｍｅｎｔｓｉｎＭｅｔａｌ-ＰｏｏｒＳｔａｒｓＺＨＯＵＧｕｉ-ｄｅ ( 4) . 7……………………………………………………………………ＳｏｌａｒＰｈｙｓｉｃｓ　ＲａｄｉｏＡｓｔｒｏｎｏｍｙＴｈｅＤｙｎａｍｉｃａｌＦｅａｔｕｒｅｏｆＦｉｌａｍｅｎｔｓｉｎＡＲ750 0ＪＩＡＮＧＹｕｎ -ｃｈｕｎ ,ＬＵＡＮＤｉ ( 1 ) . 1 8………ＳｏｌａｒＲａｄｉｏＭｅｔｒｉｃＷａｖｅＥｖｅｎｔｓＦｒｏｍＡｃｔｉｖｅＲｅｇｉｏｎ 653 8…     

人造卫星数据库管理系统中ORACLE FORMS的应用

ＯＲＡＣＬＥ ＦＯＲＭＳ是ＯＲＡＣＬＥ数据库系统应用程序重要的开发工具之一,它具有良好的窗口,模拟块以及触发器等功能,同时它作为ＯＲＡＣＬＥ大家族中的一员,与ＯＲＡＣＬＥ的其他应用工具又是分不开的。本文结合实例详细地介绍了ＯＲＡＣＬＥ ＦＯＲＭＳ在开发人造卫星数据库管理系统中的应用。     

太阳硬X射线爆发与行星际质子流量的统计关系

本文根据１９８０年２月至１９８９年１１月期间ＳＭＭ卫星的硬Ｘ射线（ＨＸＲ）暴观测和ＧＯＥＳ卫星的行星际质子积分流量观测，证认出４８个共同样品，统计发现ＨＸＲ暴的寿命Ｔｄ（ｓ）、峰值记数率Ｆｘ（ｃ／ｓ）和爆发期间发射的总光子数ｃ的对数值，与行星际质子积分流量（被归一到耀斑本地）值Ｆｐ的对数值之间，均具有特别显著的线性关系，其中以ｌｏｇＦｐ与ｌｏｇＣ的线性关系为最好，其拟合方程是ｌｏｇＦｐ（＞１０ＭｅＶ）＝一０．６０４＋０．５３８ｌｏｇＣ，相关系数ｒ为０．７０，相对标准误差为０．２８．文中对质子积分流量的预测精度也作了讨论，并给出了置信区间。     

A Millimeter-Wave Radio Telescope Project at Seoul National University

1　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＤｅｐａｒｔｍｅｎｔｏｆＡｓｔｒｏｎｏｍｙａｔＳｅｏｕｌＮａｔｉｏｎａｌＵｎｉｖｅｒｓｉｔｙｉｓｃａｒｒｙｉｎｇｏｕｔａｐｒｏｊｅｃｔｔｏｂｕｉｌｄａｒａｄｉｏｏｂｓｅｒｖａｔｏｒｙ ,ｔｈｅＳｅｏｕｌＲａｄｉｏＡｓｔｒｏｎｏｍｉｃａｌＯｂｓｅｒｖａｔｏｒｙ (ＳＲＡＯ) .Ｔｈｅｏｂｓｅｒｖａｔｏｒｙｗｉｌｌｏｐｅｒａｔｅａ 6 ｍｍｉｌｌｉｍｅｔｅｒ ｗａｖｅｔｅｌｅｓｃｏｐｅ .ＴｈｅａｎｔｅｎｎａｉｓｉｄｅｎｔｉｃａｌｔｏｔｈｏｓｅｏｆｔｈｅＢＩＭＡ (Ｂｅｒｋｅ ｌｅ…     

Vector Magnetograph Observations by the Solar Flare Telescope at Boao

1　ＩｎｔｒｏｄｕｃｔｉｏｎＡｆｉｌｔｅｒ ｂａｓｅｄｖｅｃｔｏｒｍａｇｎｅｔｏｇｒａｐｈｉｓａｔｔａｃｈｅｄｔｏｔｈｅＳｏｌａｒＦｌａｒｅＴｅｌｅｓｃｏｐｅ (Ｍｏｏｎｅｔａｌ.1 996 ,Ｐａｒｋｅｔａｌ.1 997)ａｔｔｈｅＢｏｈｙｕｎｓａｎＯｐｔｉｃａｌＡｓｔｒｏｎｏｍｙＯｂｓｅｒｖａｔｏｒｙ (ＢＯＡＯ) ,ＷｈｉｃｈｕｓｅｄａｖｅｒｙｎａｒｒｏｗｂａｎｄＬｙｏｔｆｉｌｔｅｒａｎｄＫＤ Ｐｃｒｙｓｔａｌｓｆｏｒｐｏｌａｒｉｍｅｔｒｉｃｏｂｓｅｒｖａｔｉｏｎｓ .ＴｈｅＳｔｏｋｅｓｐａ ｒａｍｅｔｅｒｓａｒｅｍ…     

太阳硬X射线爆发行星际质子流量的统计关系

本文根据１９８０年２月至１９８９年１１月期间ＳＭＭ卫星的硬Ｘ射线暴观测和ＧＯＥＲ卫星珠卫星际质子积分流量Ｆｐ观测，证认出４８个共同样品，统计发现ＨＸＲ暴的寿命ＴＤ，峰值记数率Ｆｘ和爆发期间射的总光子数Ｃ的对数值，与行星际质子积分流量（初归一到耀斑本地）值Ｆｐ的对数值之间，均具有特别显著的线性关系，其中以ｌｏｇＦｐ与ｌｏｇＣ的线性关系的最好，其拟合方程是ｌｏｇＦｐ＝－６．０４＋０．５３８ｌｏｇＣ，相     

An Universal Birefringent Filter Developed for Japan

ＯｎＪｕｌｙｏｆ1 998,ＮａｎｊｉｎｇＡｓｔｒｏｎｏｍｉｃａｌＩｎｓｔｒｕｍｅｎｔＲｅｓｅａｒｃｈＣｅｎｔｅｒ (ＮＡＩＲＣ)ｏｆＣｈｉｎｅｓｅＡ ｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ,ｈａｓｐｒｏｖｉｄｅｄａＵｎｉｖｅｒｓａｌＢｉｒｅｆｒｉｎｇｅｎｔＦｉｌｔｅｒ (ＵＢＦ)ｔｏＴｏｋｙｏＭｅｉｓｅｉＵｎｉｖｅｒ ｓｉｔｙｔｈｒｏｕｇｈＮｉｋｏｎＣｏｒｐｏｒａｔｉｏｎｏｆＪａｐａｎ .1　Ｏｐｔｉｃａｌｓｃｈｅｍｅ (Ｆｉｇ 1 )ＴｈｅＵＢＦｉｓｃｏｍｐｏｓｅｄｏｆｓｉｘｔｕｎａｂｌｅＬｙｏｔｅｌｅｍｅｎｔｓＬ1 Ｌ6,…     

LAGEOS II perigee rate and eccentricity vector excitations residuals and the Yarkovsky-Schach effect

We have analysed LAGEOS II perigee rate and eccentricity vector excitation residuals over a period of about 7.8 years, adjusting and computing the satellite orbit with the full set of dynamical models included in the GEODYN II software code. The long-term behaviour of these orbital residuals appears to be characterised by several distinct frequencies which are a clear signature of the Yarkovsky-Schach perturbing effect. This non-gravitational perturbation is not included in the GEODYN II models for the orbit determination and analysis. Through an independent numerical analysis, and using the new LOSSAM model to represent the spin-axis behaviour of the satellite, we propagated the Yarkovsky-Schach effect on LAGEOS II perigee rate and compared the results obtained with the orbital residuals. We have thus been able to satisfactorily fit the amplitude of the Yarkovsky-Schach effect to the observed residuals. Our approach here has proven very successful with very positive results. We have been able to obtain a fractional reduction of about 40% of the post-fit rms with respect to the pre-fit value. When analysing the eccentricity vector residuals, we have been able to obtain a better result in the case of the real component, with a fractional reduction of the post-fit rms of about 49% of the initial value. The analysis of the effect's imaginary component in the eccentricity vector rate is more complicated and deserves additional scrutiny. In this case we need a deeper study which includes the analysis of other unmodelled and mismodelled effects acting on the imaginary component. The study performed in this paper will be of significant relevance not only for the geophysical applications involving LAGEOS II orbit analysis, but also for a refined re-analysis of the general relativistic precession produced by the Earth angular momentum, i.e., the Lense-Thirring effect.     

Orbit Determination of the Asteroid (469219) Kamoòalewa and Its Error Analysis

As an Earth co-orbital asteroid, (469219) Kamoòalewa is a near earth object (NEO) with high value of research, and one of the targets explored by the first Chinese asteroid exploration mission. Given its orbit characteristics, we build a refined dynamical model for this asteroid, in which the effects induced by nonspherical gravitational fields of the Sun, the Earth, and the Moon are combined. On the basis of the dynamical model of the asteroid (469219) Kamoòalewa, its orbit is determined with optical data from 2004 to 2018 available on the Minor Planet Center (MPC) database. The root mean square error of post-fit residuals is about 0.2 arc second (comparable with that of the Jet Propulsion Laboratory (JPL)/Horizons), and the post-fit residuals of optical observations in 2004 are decreased. At the end, we implement error analysis on the asteroid (469219) Kamoòalewa's orbit in detail, and also predict its orbit error at the time interval between 2020 and 2025.     

小行星(469219) Kamo`oalewa轨道的确定与误差分析

作为一颗与地球共轨道的小行星,(469219)Kamo'oalewa是一个具有很高研究价值的近地小天体,也是中国首次小行星探测计划的目标天体之一.针对其轨道特性,建立了兼顾太阳、地球和月球非球形引力作用的小行星动力学模型.并在该模型的基础上,利用国际小行星中心(Minor Planet Center,MPC)提供的2004|2018年间的光学观测数据对该小行星的轨道进行确定.拟合后观测残差的均方根误差约为0:2″(与美国喷气推进实验室的Horizons在线历表系统相当),其中2004年期间数据的观测残差有所改进.最后,对小行星(469219)Kamo'oalewa的轨道误差进行了详细分析,并预报了2020-2025年期间该小行星的轨道误差.     

Spacecraft Doppler tracking with possible violations of LLI and LPI:upper bounds from one-way measurements on MEX

We analyze the post-fit residuals of one-way Doppler tracking data from the Mars Express(MEX) spacecraft to test possible violations of local Lorentz invariance(LLI) and local position invariance(LPI).These one-way Doppler observations were carried out on 2011 August 7 for about 20 minutes at Sheshan Station of Shanghai Astronomical Observatory in China.These downlink signals were sent by MEX for telemetry at X-band.Because we are not able to decode the data in the form of telemetry and separate them from the carrier frequency,this makes the post-fit residuals of the Doppler data degrade to the level of 0.1 m s~(-1).Even so,the residuals can still impose upper bounds on LLI and LPI at 10~(-1),which is consistent with the prediction based on our analysis of the detectability.Although the upper bounds given by three-way Doppler tracking of MEX are better than those obtained in the present work,one-way Doppler measurements still provide a unique chance to test possible violations of LLI and LPI far from the ground stations.     

A New Solution Assessment Approach and Its Application to Space Geodesy Data Analysis

The statistics of the residuals are used in this paper to perform a quality assessment of the solutions from space geodesy data analysis. With the stochastic estimation and the relatively arbitrary empirical parameters being employed to absorb unmodelled errors, it has long been noticed that different estimate combinations or analysis strategies may achieve the same level of fitting yet result in significantly different solutions. Based on the postulate that no conceivable signals should remain in the residuals, solutions of the same level of root mean square error (RMS) and variance–covariance may be differentiated in the sense that for reasonable solutions, the residuals are virtually identical with noise. While it is possible to develop complex noise models, the Gaussian white noise model simplifies the solution interpretation and implies the unmodelled errors have been smoothed out. Statistical moments of the residuals as well as the Pearson chi-square are computed in this paper to measure the discrepancies between the residuals and Gaussian white noise. Applying to both satellite laser ranging (SLR) and global positioning system (GPS) data analysis, we evaluate different parameter estimate combinations and/or different strategies that would be hardly discriminated by the level of fitting. Unlike most solution assessment methods broadly termed as external comparison, no information independent of the data analyzed is required. This makes the immediate solution assessment possible and easy to carry out. While the external comparison is the best and most convincing quality assessment of the solution, the statistics of the residuals provide important information on the solutions and, in some cases as discussed in this paper, can be supported with external comparison.     

Spacecraft Doppler tracking with possible violations of LLI and LPI: preliminary bounds on LLI from Mars Express

Three-way spacecraft Doppler tracking is currently widely used and it plays an important role in the control and navigation of deep space missions. Using the theory of three-way Doppler tracking, including possible violations of the local Lorentz invariance(LLI) and the local position invariance(LPI), we analyze the post-fit residuals of three-way Doppler tracking data of Mars Express. These Doppler observations were carried out from August 7th to 8th in 2009, with an uplink station administered by the European Space Agency at New Norcia in Australia and three downlink stations at Shanghai, Kunming and Urumqi in China. We find that, although these observations impose preliminary bounds on LLI at the level of 10-2, they are not suitable for testing LPI because of the configuration of these stations and the accuracy of the observations.To our knowledge, this is one of the first attempts in China to apply radio science to the field of fundamental physics.     

The distance to the Galactic center determined by OB stars

The OB stars are concentrated near the Galactic plane and should permit a determination of the distance to the Galactic center. van Leeuwen’s new reduction of the Hipparcos catalog provides, after 824 Gould belt stars have been excluded, 6288 OB stars out to 1 kpc and Westin’s compilation an additional 112 stars between 1 kpc and 3 kpc. The reduction model involves 14 unknowns: the Oort A and B constants, the distance to the Galactic center R ₀, 2 second-order partial derivatives, the 3 components of solar motion, a K term, a first order partial derivative for motion perpendicular to the Galactic plane, a second-order partial for acceleration perpendicular to the plane, two terms for a possible expansion of the OB stars, and a C constant. The model is nonlinear, and the unknowns are calculated by use the simplex algorithm for nonlinear adjustment applied to 14313 equations of condition, 12694 in proper motion and 1619 in radial velocity. Various solutions were tried: an L₁ solution, a least squares solution with modest (2.7 %) trim of the data, and two robust least squares solutions (biweight and Welsch weighting) with more extreme trimming. The Welsch solution seems to give the best results and calculates a distance to the Galactic center 6.72±0.39 kpc. Statistical tests show that the data are homogeneous, that the reduction model seems adequate and conforms with the assumptions used in its derivation, and that the post-fit residuals are random. Inclusion of more terms, such as streaming motion induced by Galactic density waves, degrades the solution.     

Application of Accelerometer Data in Precise Orbit Determination of GRACE -A and -B

We investigate how well the GRACE satellite orbits can be determined using the onboard GPS data combined with the accelerometer data.The preprocessing of the accelerometer data and the methods and models used in the orbit determination are presented.In order to assess the orbit accuracy,a number of tests are made,including external orbit comparison,and through Satellite Laser Ranging (SLR) residuals and K-band ranging (KBR) residuals.It is shown that the standard deviations of the position differences between the so-called precise science orbits (PSO) produced by GFZ,and the single-difference (SD) and zero-difference (ZD) dynamic orbits are about 7 cm and 6 cm,respectively.The independent SLR validation indicates that the overall root-mean-squared (RMS) errors of the SD solution for days 309-329 of 2002 are about 4.93cm and 5.22cm,for GRACE-A and B respectively; theoverall RMS errors of the ZD solution are about 4.25 cm and 4.71 cm,respectively.The relative accuracy between the two GRACE satellites is validated by the KBR data to be on a level of 1.29 cm for the SD,and 1.03 cm for the ZD solution.     

A Study on the Reliability of the Ionospheric VTEC and Satellite DCB Derived from a Regional GPS Network

According to the requirement of high-precision satellite navigation, we have introduced the method for the quasi-realtime monitoring of variations of the regional ionospheric total electron content (TEC) and GPS satellite differential code bias (DCB), based on the dual-frequency carrier-phase smoothed pseudorange data obtained from a regional GPS network in China. Especially, we have studied the feasibility of retrieving DCB independently from the regional GPS networks with different sizes. For this purpose, 3 regional networks based on the countrywide GPS stations are investigated. The comparisons of the computed DCB and VTEC(vertical total electron content) with those of CODE(the Center for Orbit Determination in Europe) indicate that in order to realize a reliable quasi-realtime measurement of DCB by a regional network, there is a certain requirement on the size of the regional network, and that the relative accuracies of the quasi-realtime VTEC and DCB measured by using a Chinese GPS regional network can reach 2.0TECu and 0.25 ns, respectively.     

四种综合脉冲星时算法比较

由单颗脉冲星定义的脉冲星时受多种噪声源的影响,其短期和长期稳定度都不够好.为了削弱这些噪声源对单脉冲星时的影响,可以采取合适的算法对多个单脉冲星时进行综合得到综合脉冲星时,从而提高综合脉冲星时的长期稳定度.文中介绍4种综合脉冲星时算法:经典加权算法、小波分析算法、维纳滤波算法和小波域中的维纳滤波算法,将这4种算法分别应用于Arecibo天文台对两颗毫秒脉冲星PSR B1855+09和PSRB1937+21观测得到的计时残差并作出比较.