Statistical property of the Chandler wobble excitation function

The Chandler wobble excitation function (hereinafter, geodetic excitation) is obtained by removing the seasonal components and low frequency components with periods from several years to decades from the polar motion excitation function derived from SPACE2002 series. The geophysical excitation functions of the individual AAM, OAM, HAM, and two combined excitations of the AAM OAM and AAM OAM HAM at ld, 5d, lm and 3m intervals are statistically tested for the hypothesis of the normality, and then tested for the hypotheses of identical distribution between the geodetic and the geophysical excitations. The results show that, among the total 16 components of the two combined excitation functions at ld, 5d, lm and 3m intervals, most follow random normal processes, the hypotheses of identical distribution between the geodetic excitation and the two combined excitation are acceptable, while most of the hypotheses of identical distribution between the geodetic excitation and the individual excitations of the AAM, OAM, and HAM are rejectable. These results elucidate from a new point of view, that the excitations from AAM, OAM, and HAM are the main sources of the Chandler wobble, and the Chandler wobble excitation function is of a random normal property.     

液核地球极移和章动的联合动力学方程

以经典的液核地球自转动力学理论为基础,通过引入章动坐标系相对惯性空间的运动,建立了液核地球极移和章动的联合动力学方程。主要内容有：（1）顾及了高阶岁差章动力矩对地球自转的影响;（2）引入了摄动周期满足T≤2/3d和T≥2d的其他因素（大气、海洋和地表水分布变化等）对地球自转的影响;（3）建立了自转轴极移和任一天球参考轴极移和章动之间的理论关系;（4）建立了液核地球极移和章动的联合动力学方程,试图用统一的方法研究极移和章动。作者给出的理论公式可为动力大地测量学和天文地球动力学的研究提供理论参考和依据。     

极坐标系下的目标运动模型研究

由于传感器对目标的观测采用的极坐标系或球坐标系与目标运动模型采用的直角坐标系之间是非线性关系,导致按照一般方法难以对目标运动状态做精确的估计.借助直角坐标系下的目标运动模型,导出极坐标系下的目标运动模型,并分别对CV模型和CA模型对应的极坐标系目标运动模型进行了仿真研究.仿真结果表明:依据此模型建立的卡尔曼滤波器对目标运动状态的估计是有效的.     

Determination of the controlled landing trajectory of Chang’E-1 satellite and the coordinate analysis of the landing point on the Moon

Based on the tracking observations of radio ranges and VLBI delays of Chang’E-1 (CE-1) satellite during the controlled landing on the Moon on March 1, 2009, the landing trajectory and the coordinates of the landing point are determined by positioning analysis. It is shown that the landing epoch (the emission epoch of the last signal) of CE-1 satellite on the Moon was at UTC8h13m6.51s. The lunar longitude, latitude and surface height of the landing point in the lunar primary axes frame are respectively 52.27...     

极坐标法加工凸轮的研究

使用极坐标法在数控线切割机床完成精度± 0 .0 0 5mm ,粗糙度 3.2 μm ,生产率 80mm2 /min的凸轮加工 ,本文对其加工原理和编程方法进行了详细的阐述和研究。     

地球自转对地球重力场时变特征影响的理论研究

 精密和详细测定地球重力场及其时间变化,是目前卫星重力测量的主要课题.地极移动和日长变化导致地球引力位系数产生时变特性并引起重力的摄动.根据理论力学的基本概念,详细推导了由于地球自转引起的地球引力位系数变化、重力摄动和垂线偏差的表达式,并定量地研究了极移和日长变化对测站重力观测值的影响.同时基于EGM96地球引力位模型,给出了地球引力位系数C₂¹和S₂¹的理论公式.研究表明在高精度的空间大地测量中要顾及到地球自转变化引起的一系列效应.     

半圆型量子线中的电子运动

在平面极坐标系下,导出电子在半圆型量子线中运动的等效薛定谔方程,与一维自由电子运动的不同之处,方程中含有一有效势Veff.讨论了有效势只与量子线的曲率有关,而不受外加限制势的影响.并说明了没有有效势时,电子的运动不符合物体运动的基本规律.     

Analysis of the ionosphere wave-motion with GPS

The periodic solar activities strongly affect the ioniza-tion of the ionosphere. Sudden enhancements in soft and hard solar X-ray and EUV radiation during solar flare can produce an immediate increase in ionospheric ionization in various degrees at different heights; altogether, they are called sudden ionospheric disturbances (SIDs), which are generally recorded as sudden increase of total electron content (SITEC), the short wave fadeout (SWF), sudden frequency deviation (SFD), sudden ph…     

Improvement of orbit determination for geostationary satellites with VLBI tracking

China’s COMPASS satellite navigation system consists of five or more geostationary (GEO) satellites.The roles of GEO satellites are to improve the regional user’s positioning accuracy and provide the continuous Radio Determination Satellite Service.The motion of GEO satellites relative to a ground tracking station is almost fixed,and regular orbit maneuvers are necessary to maintain the satellites’ allocated positions above the equator.These features present difficulties in precise orbit determination (POD).C-band ranging via onboard transponders and the L-band pseudo-ranging technique have been used in the COMPASS system.This paper introduces VLBI tracking,which has been successfully employed in the Chinese lunar exploration programs Chang’E-1 and Chang’E-2,to the POD of GEO satellites.In contrast to ranging,which measures distances between a GEO satellite and an observer,VLBI is an angular measurement technique that constrains the satellite’s position errors perpendicular to the satellite-to-observer direction.As a demonstration,the Chinese VLBI Network organized a tracking and orbit-determination experiment for a GEO navigation satellite lasting 24 h.This paper uses the VLBI delay and delay-rate data,in combination with C-band ranging data,to determine the GEO satellite’s orbit.The accuracies of the VLBI delay and delay rate data are about 3.6 ns and 0.4 ps/s,respectively.Data analysis shows that the VLBI data are able to calibrate systematic errors of the C-band ranging data,and the combination of the two observations improves orbit prediction accuracy with short-arc data,which is important for orbital recovery after maneuvers of GEO satellites.With the implementation of VLBI2010,it is possible for VLBI to be applied in the COMPASS satellite navigation system.     

Combined adjustment project of national astronomical geodetic networks and 2000'''' national GPS control network

The combined adjustment of astronomical geode tic networks and the 2000’national GPS control net work is a national geodetic project based on the pre sent necessities and long term program of national e conomic development. This project has profound sci entific, social and economic significance, and willproduce an effect on developments of space scienceand national defense construction as well as geodesyitself.China took part in the second international radioobservational projec…     

关于地球受迫章动的简正模表达式

章动序列的计算依赖于受迫章动的简正模表达式，简正模表达式涉及到一些系数，包括简正模的本征频率和某些常数。本文讨论了两种不同简正模表达式以及它们的系数间的关系，指出了某些作者给出的系数数值的缺陷，计算了内核动力学对受迫章动的影响，结果表明其影响已在目前ＶＬＢＩ可检测的量级内。章动序列的理论值可通过选定一个地球模型和其它方法推算出，然后将章动序列的理论值与ＶＬＢＩ观测资料进行比较，从而可改进章动序列并为研究模型地球和实际地球的差异提供有用的信息。     

Rupture of the 2004 Sumatra-Andaman earthquake inferred from direct P-wave imaging

The Sumatra-Andaman earthquake on December 26, 2004 is the first well recorded gigantic earthquake (moment magnitude MW 9.3) by modern broadband seismic and Global Positioning System networks. The rich seismic and geodetic recordings have documented unprecedented details about the earthquake rupture, coseismic and postseismic deformations. This is a report of detailed images of the rupture process using the first-arriving compressional waves recorded by the China National Digital Seismic Network (CNDSN). An improved imaging condition was employed to account for the sparse distribution of the CNDSN stations. The resulting images are consistent with the major rupture features reported by previous seismic and geodetic studies. It is found that the earthquake rupture initiated at offshore of northwestern Sumatra and propagated in the north northwest direction at a speed of 2.7 ± 0.2 km/s. The rupture continued for at least 420 s and extended about 1200-1300 km along the Andaman trough with two bursts of seismic energy.     

利用VB实现青海海东城市群网络RTK坐标转换

本文根据大地坐标正算模型和似大地水准面模型,针对网络RTK观测的数据,利用Visual Basic 6.0程序语言工具编写了一个坐标转换程序,可以快速、精确地实现2000国家大地坐标系下平面坐标和正常高的计算.文中介绍了大地坐标到平面坐标的高斯投影正算和利用似大地水准面模型计算正常高的原理,分析了程序设计的主要流程,最后用实际算例对程序的转换效果进行了定性分析.     

极坐标系下等离子体模拟的粒子推进算法

提出了一种在极坐标系下快速推进带电粒子的等离子体粒子模拟算法,该算法在每个时间步长内对带电粒子位置附近的区域采用局部直角坐标系近似,并通过坐标变换,得到粒子运动方程求解的显式格式,从而避免了极坐标系下隐式格式直接迭代求解所带来的容许误差,并提高了计算效率.数值实验表明:显式粒子推进算法的计算速度比容许误差取10-3时的隐式算法提高了约1倍.该算法可用于轴向均匀等离子体器件和高功率微波器件的2 5维粒子模拟.     

液核地球各种轴系的表述

 之前的整体地球自转动力学理论的局限性之一,就是在数学上不能明确表述地球的各种几何轴和物理轴(Tisserand轴、自转轴、瞬时形状轴、角动量轴、CEP和CIP轴等).基于经典的液核地球自转动力学理论,建立了极移和‘章动'的联合动力学方程.由此给出了液核地球各种几何轴和物理轴的极移、岁差章动的动力学方程,明确了各种轴的定义及其之间的理论关系.     

对银河系中心超大质量黑洞候选体Sgr A*的VLBI观测研究

位于银河系中央的极其致密的非热射电源Sagittari8us A^*（Sgr A^*），被公认为最佳的超大质量黑洞候选体，其质量约为400万个太阳质量。甚长基线干涉测量（BLBI）技术以其独有的高空间分辩率为我们提供了唯一可以探讨Sgr A^*位于几个史瓦西（Schwarzschild）半径区域内天体物理性质的手段。介绍了对 Sgr A^*的VLBI研究现状和最新进展，着重论述了毫米波和亚毫米波VLBI观测对研究Sgr A^*的辐射区域的真实形状和大小，以及探索其结构随时间变化的重要性。Sgr A^*无疑是检验广义相对论将就的亚亮米波VLBI实验的最佳目标。     

Detection of unsymmetrical global tectonic change by using space geodetic data

The global tectonic change deduced from geophysical research was first identified by space geodetic data from VLBI, GPS and SLR measurements. Whether using geodesic rates or using vertical velocities of stations, three kinds of data and their integration give consistent results: within the mid-latitude belt on the Northern Hemisphere there may be about 8–10 mm/a contracting change; within the mid-latitude belt on the Southern Hemisphere there may be about 12–14 mm/a expanding change. This result not only validates the reverse global tectonic change in the Southern and Northern Hemispheres of the Earth, but also gives relatively precise quantative estimations.     

参照NRO的CRS和TRS的转换

讨论了对照非旋转原点天球参考和地球参考系的转换方法，并和经典方法进行了比较。两种转换方法在数值上基本是一致的，但新的转换方法显示出较好的优越性，它在概念上和实用上更简单，同时指出用甚长基线干涉观测确定地球定向参数的归算中，使用新的转换方法将更合适。     

Investigation of stronger diurnal ERP signals in summer derived from the VLBI CONT08 campaign

A series of very successful Continuous Very Long Baseline Interferometry Campaigns (CONT) have been carried out at irregular intervals since 1994. One of the goals is to support high-resolution earth rotation studies. The most recent CONT08 campaign was conducted with a network of 11 observatories at an increased recording rate of 512 Mbit per second over a fortnightly time span, from which stronger diurnal variations of the Earth Rotation Parameters (ERP) have been detected. We compared the high-frequency ERP from VLBI and GPS observations during CONT02, CONT05 and CONT08 with the atmospheric angular momentum functions derived from the National Centers for Environmental Prediction/National Center for Atmospheric (NCEP/NCAR) during these periods. We attribute the detected diurnal discrepancies between the theoretical models and the CONT08 observations to atmospheric excitations.