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…     

应用常规技术和GPS技术建立城市独立坐标系的讨论

介绍了应用常规技术建立的以高程面为边长归算参考面的城市坐标系和国家大地坐标系在数据处理方面的异同;以及GPS技术建立城市现代坐标系时区域性椭球的选取和GPS控制网归算到城市坐标系地面网的方法。     

National 2000’ GPS control network of China

An accurately unified national GPS network with more than 2500 stations,named"National 2000' GPS Control Net- work",signed the epoch 2000.0,has been established by integrating the existing six nationwide GPS networks of China set up by differ- ent departments with different objectives.This paper presents the characteristics of the existing GPS networks,summarizes the strategies in the integrated adjustment of the GPS network,including functional model,stochastic model as well as the adjustment principle modifi- cation.By modifying the adjustment strategies according to the characteristics of the existing GPS networks and under the support of the IGS stations,the accuracy of the integrated national GPS network is greatly improved.The datum differences among the sub networks disappear,the systematic error influences are weakened,and the effects of the outliers on the estimated coordinates and their variances are controlled.It is shown that the average standard deviation for the horizontal component is smaller than 1.0 cm,the vertical component is smaller than 2.0 cm,and the three-dimensional (3-D) position of geocenter coordinates is smaller than 3.0 cm.The exterior checking ac- curacy for the 3-D position is averagely better than 1.0 cm.     

区域GPS空间基准网的建立

随着GPS的广泛应用，如何提高GPS的定位效率，实现实时定位，已经成为有待解决迫切的问题，目前RTK技术(实时动态全球定位系统)不需要数据的后处理即可快速定位，但在定位之前，需要在足够的已知点上进行观测，计算获得所需区域的坐标系统的转换参数，这在很大程度上影响了RTK的定位效率和点位的相关与一致性，此外，目前许多城市的地方坐标系统与国家坐标系统之间缺乏精确严格的换算关系，结合区域GPS空间基准网的建立项目，阐述了GPS空间基准网的布设与施测、投影与坐标系统转换等相关的数学模型和解算方法，探讨了多套参数的差异与应用，观测分量的误差对于拟合参数精度的影响等问题，并给出了相应的分析数据．基于上述方法可以获得区域统一的、精确的多套坐标系统之间的转换参数，将WGS84的大地坐标与现行实用的坐标系统如1954年北京坐标系统、80西安坐标系统以及地方坐标系统紧密联系起来，从而实现坐标系统之间实时精确的转换，为RTK实时定位奠定基础。     

基于抗差估计的变形监测基准网坐标系统转换

为监测地下煤炭开采对某矿工业广场内主、副井筒的影响,布设了由10个点构成的GPS基准网,从而为由54个监测点构成的井筒监测网提供在矿区坐标系统下的变形分析基准;在求解坐标转换参数时,为克服转换基准点中存在的位移对求参的影响,提出了采用抗差估计理论求参的模型及数据处理流程,并建立转换后GPS网的质量评价模型。根据对GPS基准网的处理结果,采用抗差估计求参,有利于保留GPS技术高精度的特点。     

矿区地表变形GPS监测网的动态平差

应用GPS取代传统的地表变形监测网可以提高外业观测的效率。而GPS观测值是三维基线向量,平差结果是地心坐标系的三维坐标。通过多次重复观测数据的动态平差。可获得各监测站的三维移动、三维移动速率,并可求出加速率。本文研究了三维监测网的分期动态平差方位、平差基准的选取和平差成果的利用。     

GPS卫生测量

在介绍GPS系统的构成、定位原理之基础上,说明了WGS－84坐标与地方坐标的转换过程、GPS观测量的误差来源以及GPS网平差。     

手持GPS坐标系统转换参数的求解方法

不同的测量成果均对应于不同的坐标系。GPS定位结果属于协议地心坐标系,即WGS-84坐标系。而实用的常规测量成果属于国家参心坐标系(北京54坐标系、西安80坐标系)或地方坐标系,因此必须实现GPS测量成果的转换。本文介绍的就是我们在实际工作中求解该参数的方法。     

顾桥煤矿GPS基准网坐标转换的高崩溃污染率抗差估计

为确保顾桥煤矿D级GPS平面基准网坐标系统转换后的质量,克服转换基准点中存在的位移对转换成果的影响,基于高崩溃污染率抗差估计理论,建立了坐标系统转换参数的估计模型及转换后GPS网的质量评价模型。顾桥煤矿D级GPS网转换后的成果表明,高崩溃污染率抗差估计能够实现平差系统对存在位移的转换基准点进行自动准确探测的目的,保留了GPS技术高精度的特点,为该矿区建立了可靠的测绘基准。     

GPS大坝变形监测网数据处理模型

考虑到GPS大坝变形监测网的特殊性，提出了以站心地平坐标系为参考坐标系的GPS大坝三维变形监测网的数据处理模型；提出了应用模糊数学中的聚类分析方法对拟稳点（或固定基准点）的相对稳定性进行检验的数学模型；提出了平差采用拟稳平差的方法．用VB语言开发了GPS大坝三维变形监测网的数据处理软件系统，并对某大坝GPS变形监测网的三期观测数据进行了平差计算，其结果表明，所提出的数学模型更适合于GPS大坝变形监测网的数据处理．     

Contemporary crustal movement of continental China obtained by global positioning system (GPS) measurements

We obtain a unified horizontal velocity field of continental China and vicinity through measurements at 81 GPS stations provided by the National Key Infrastructure Project, Crustal Movement Observation Network of China. The velocity field delineates patterns of movements and deformation of active crustal blocks in continental China under the Eurasia-fixed reference frame. The space-based geodesy also clearly shows for the first time the horizontal movement and deformation of continental China induced by indentation of the Indian plate. The data provide kinematic constraints for simulating dynamic process of continental lithospheric deformation.     

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.     

多参考站网络的虚拟观测值生成算法

讨论了GPS观测值误差改正方法,提出了一种基于多参考站的GPS观测值向流动站用户发布虚拟观测值的算法.该算法通过参考站的已知精确坐标和已经解算的模糊度计算参考站间双差空间相关误差,然后内插局域网内任意一点空间相关误差作为改正数.当只使用3个参考站时使用线性内插法,多于3个参考站时使用曲面拟合或最小二乘平差方法等内插方法.用内插获得的改正数改正离流动站最近的参考站(主参考站)的观测值,形成虚拟观测值,然后发送给流动站用户,流动站用户仍然应用已有的单参考站GPS定位算法进行定位.通过对江苏局域参考站网络收集的实测数据计算分析证明了本文算法的有效性,达到厘米级定位精度.     

GPS网与地面网约束条件的序贯平差

采用简洁的方式,导出了固定参数序贯平差的计算公式,并对ＧＰＳ网与地面网中存在的固定边长和固定坐标方位角等约束条件进行序贯平差。结合矿区实例,讨论了约束条件的精度对ＧＰＳ网精度的影响问题。     

固定转换参数的GPS网平差与坐标转换模型

分析了起始数据误差与坐标轴指向变化对于转换参数的影响 ,提出了采用固定转换参数的GPS基线向量与地面已知数据进行联合平差与转换的模型 ,探讨了采用该模型计算时应该注意的问题 .利用这一模型处理了上海地铁M8线GPS控制网的数据 ,结果表明 :当已知点位于GPS网的一侧时 ,采用这一模型能够显著地提高GPS控制网的外符合精度 .     

基于不同参考框架的GPS卫星天线校验

重新估计了基于不同参考框架的GPS卫星天线PCO(相位中心偏差)和PCV(相位中心变化)参数.计算过程中,通过固定测站天线的PCO和PCV,并将测站坐标强约束至不同的参考框架之下,降低了GPS卫星天线参数和接收机天线参数以及参考框架参数之间的相关性.结果显示,基于不同参考框架的同类型卫星天线PCV差异的平均值为0.726mm;与IGS发布值差异的平均值为0.844mm;基于新公布的IGS14参考框架的GPS卫星天线PCO估计结果与IGS(国际GNSS服务)发布值差异的平均值为-14.4mm,基于IGb08参考框架的卫星天线PCO估计结果与IGS发布值差异的平均值为-16.8 mm.以上结果表明,本措施提高了GPS卫星相位中心PCO/PCV的一致性,从而也能提高GNSS(global navigation satellite system)技术用于框架传递的连续性.     

Static slip model of the M w 9.0 Tohoku (Japan) earthquake: Results from joint inversion of terrestrial GPS data and seafloor GPS/acoustic data

Based on co-seismic displacements recorded by terrestrial GPS stations and seafloor GPS/acoustic stations, the static slip model of the 2011 Mw 9.0 Tohoku earthquake was determined by inverting the data using a layered earth model. According to a priori information, the rupture surface was modeled with a geometry that is close to the actual rupture, in which the fault dip angle increases with depth and the fault strike varies with the trend of the trench. As shown by the results inferred from the joint inversion, the "geodetic" moment is 3.68 × 10 22 Nm, corresponding to Mw 9.01, and the maximum slip is positioned at a depth of 13.5 km with a slip magnitude of 45.8 m. Rupture asperities with slip exceeding 10 m are mainly distributed from 39.6 to 36.97°N, over a length of almost 240 km along the trench. The slip was mostly concentrated at depths shallower than 40 km, up-dip of the hypocenter. "Checkerboard" tests reveal that a joint inversion of multiple datasets can resolve the slip distribution better than an inversion with terrestrial GPS data only-especially when aiming to resolve slip at shallow depths. Thus, the joint inversion results obtained by this work may provide a more reliable slip model than the results of other studies that are only derived from terrestrial GPS data or seismic waveform data.     

适用于编制广西地图的宽带高斯—克吕格投影

根据广西的地理位置,设计了以108°为中央经线的宽带高斯——克吕格投影。给出了2000国家大地坐标系的WGS84地球椭球参数的平面直角坐标、长度比和子午线收敛角的计算程序和成果。本投影与除百万分之一地形图外的国家基本比例尺地形图的投影一致,面积变形不超过千分之二,具有便于地图内容转绘的特点,是一种适用于编制广西地图的地图投影。     

基于似单差法的井筒沉降监测试验与结果分析

为监测地下煤炭开采对某矿工业广场内主、副井筒的影响,布设了由54个监测点和2个基准点组成的监测网。监测网的基准时段测量采用静态GPS相对定位技术和三等几何水准,以此作为沉降监测基础;监测时段外业观测方法与基准时段的相同,但沉降量采用以似单差法为理论的GQuickS软件进行解算,并与几何水准测得的沉降量进行比对分析,结果表明,采用似单差法进行沉降监测可达到三等水准监测的要求。     

A new way to generate seismic waves for continental crustal exploration

An airgun experiment was conducted in a reservoir,with the total volume of the airgun array being 6000 cubic inch. The energy released by one excitation was estimated to be 6.68×106 J,which corresponded to a 3.4 kg TNT explosion. A 180 km long profile composed of 100 portable short period seismometers was deployed as a receiver system of the airgun signals. Two remarkable results can be drawn from the experiment: (1) the airgun explosion is harmless to the dam and the fish,and this kind of airguns can be regarded as a green and environmental protection seismic source on land; (2) seismic wave gener-ated by this airgun source can be recorded by permanent stations with offset larger than 200 km. And the wave amplitudes recorded by nearby and remote stations are equivalent to the wave generated by 800 kg dynamite explosion. The airguns can be used as a light to illuminate the continental crustal structure of an area of about 100000 km2.