Horizontal crustal deformation in Chinese Mainland analyzed by CMONOC GPS data from 2009-2013

In this study, we analyze the regional GPS data of Crustal Movement Observation Network of China （CMONOC） observed from 2009-2013 using the BERNESE GPS software, and then the preliminary results of horizontal velocity field and strain rate field are presented, which could reflect the overall deformation features in the Chinese mainland from 2009-2013. Besides, the velocity error and the probable factors that could influence the estimate of long-term deformation are also discussed.

Inversion Precipitable Water Vapor by GPS Observation of CMONOC

In this study, we have processed the GPS （Global Position System） and meteorological data from about 220 stations of CMONOC （Crustal Movement Observation Network of China in short） observed in 2014 by GAMIT software. The comparison result of ZTD （zenith total delay） calculated by GPS data and IGS （International GNSS （Global Navigation Satellite System） Service） ZTD product shows that the tropospheric delay based on calculation of CMONOC project data is accurate and reliable. Meanwhile, the PWV （precipitable water vapor） correlation coefficients between GPS observation and upper air sounding is close to 1, which proves that GPS observation data generated in CMONOC project applied to the weather forecast research is feasible. In addition, we make an isoline image for PWV distribution per hour on all stations covered the whole Chinese land area using interpolation algorithms. We observe obvious feature that the precipitable water in north and western area is less than south and east area all over this year. High latitudes area may be dry and low latitudes area is wet.

On simulation of precise orbit determination of HY-2 with centimeter precision based on satellite-borne GPS technique

The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so that the observations are not openly released. In order to study the precise orbit determination precision and procedure for HY-2 based on the satellite- borne GPS technique, the satellite-borne GPS data are simulated in this paper. The HY-2 satellite-borne GPS antenna can receive at least seven GPS satellites each epoch, which can validate the GPS receiver and antenna design. What＇s more, the precise orbit determination processing flow is given and precise orbit determination experiments are conducted using the HY-2-borne GPS data with both the reduced-dynamic method and the kinematic geometry method. With the 1 and 3 mm phase data random errors, the radial orbit determination precision can achieve the centimeter level using these two methods and the kinematic orbit accuracy is slightly lower than that of the reduced-dynamic orbit. The earth gravity field model is an important factor which seriously affects the precise orbit determination of altimeter satellites. The reduced-dynamic orbit determination experiments are made with different earth gravity field models, such as EIGEN2, EGM96, TEG4, and GEMT3. Using a large number of high precision satellite-bome GPS data, the HY-2 precise orbit determination can reach the centimeter level with commonly used earth gravity field models up to above 50 degrees and orders.

Geometric dilution of precision for GPS single-point positioning based on four satellites

To improve the positioning accuracy in GPS point positioning, the geometric dilution of precision （GDOP） including HDOP, VDOP, TDOP, PDOP is commonly considered. The properties of the DOP for the GPS satellite navigation system are studied and the coordinate system is improved in order to decrease the amount of variables. In the end, by simulation and discussing the results, the corresponding conclusions are presented.

Measuring the Accuracy and Precision of the Garmin GPS Positioning in Forested Areas： A Case Study in Taxiarchis-Vrastama University Forest

In this paper, it is attempted to examine and compare different orientation, one recreational and another more precise, in the performance of two （global positioning system） receivers of forested areas. In doing this, a field test on horizontal and vertical positional errors of GPS positioning at different points in the forested area of Taxiarchis-Vrastama University forest was conducted. The two GPS receivers were used to determine the positional accuracy of a selected number of points under tree canopies. Specifically, the precision and accuracy of Garmin＇s GPS positioning at different points were calculated and compared with the corresponding positioning and accuracy of another GPS system, namely the TOPCON GPS. By the calculation of various measures of accuracy and precision suitable for GPS receivers and the use of statistical methods, accuracy between the different receivers differed significantly is shown. Also, regression analysis revealed that the basal area and the number of available satellites are the most important factors for predicting position error.

不同纬度GPS/BDS-3精密单点定位性能分析

为分析不同纬度区域GPS/BDS-3组合精密单点定位精度及其收敛时间,实验选取了MGEX(Multi-GNSS experiment)7个测站连续14 d的观测数据,对GPS/BDS-3组合进行精密单点定位(PPP)技术定位性能分析,并与GPS、BDS-3单系统进行对比。结果表明,无论是静态定位还是动态定位模式下,由于低纬度地区电离层较为活跃,导致数据质量较差,测站的收敛时间比高纬度测站长。此外,在静态定位模式下,GPS/BDS-3组合在水平方向定位精度优于0.8 cm,高程方向优于1.4 cm;GPS/BDS-3组合对于BDS-3单系统而言在水平方向定位精度提高了26.3%,高程方向提高了42.9%。在动态定位模式下,GPS/BDS-3组合在水平方向定位精度优于1.8 cm,高程方向优于3.8 cm;GPS/BDS-3组合对于BDS-3单系统而言在水平方向定位精度提高了35.59%,高程方向提高了56.10%。

宿豫县GPS平面控制测量与精度分析

文章介绍了用GPS单频接收机建立宿豫县城市控制网的实践,着重讨论了网的布设方案和结果精度,并进行了精度评价和分析,最后介绍了建立城市GPS控制网,提高其测量精度的体会。

USING TLS ALGORITHM TO IMPROVE GPS POSITIONING PRECISION WITH ALTITUDE HOLD MODE

This paper presents a new method of improving Global Positioning System(GPS)positioning precision. Based on the altitude hold mode, the method does not need any other equipment. Under this constraint condition, the Total Least Squares(TLS) algorithm is used to prove that the method is effective. Theoretical analysis shows that the algorithm can significantly improve the GPS positioning precision.

基于FPGA的雷达/GPS数据融合存储系统设计

现阶段高速测绘成像雷达回波信号数据量大、传输速率快,完整的实时存储高精度GPS信息的雷达数据是测绘成像的关键,面对此类系统要求满足高精度、数据融合编帧、大容量、高速度、全程准确存储等一系列问题,该文设计一种高速雷达融合数据接口控制存储系统。该系统主控模块以FPGA作为主控芯片,接收10路30 MB/s的LVDS数据和1路GPS串口数据,并进行组合编帧,打包数据通过以太网发送给上位机,最后通过LabView上位机软件将数据存储在硬盘内。最终通过试验验证,可以完整无误地将融合采编数据存储在硬盘内。

不同接收机天线相位中心改正模型对GPS/BDS精密定位的影响

针对国产不同品牌不同型号的地面接收机天线相位中心(antenna phase center,APC)模型及仪器厂商模型差异,本文分别采用相对定位及精密单点定位(precise single-point positioning,PPP)方法,分析了GPS/BDS高精度定位中基于不同APC改正模型引起的站点估计位置差异,获得了各不同天线APC改正模型对站点估计位置影响的平均差异值.试验结果表明:不同APC改正模型对站点定位精度的影响相当,对站点估计位置在平面方向影响较小,U方向影响较大;同一种类型的天线在不同实验区域造成的影响具有较好的一致性;同品牌天线对站点估计位置的影响有一定的相似性,尤其是同品牌系列产品其相位中心的影响更为接近.

Comparison of Results of Different GPS Post-processing Software

In order to obtain high-precision GPS control point results and provide high-precision known points for various projects,this study uses a variety of mature GPS post-processing software to process the observation data of the GPS control network of Guanyinge Reservoir,and compares the results obtained by several kinds of software.According to the test results,the reasons for the accuracy differences between different software are analyzed,and the optimal results are obtained in the analysis and comparison.The purpose of this paper is to provide useful reference for GPS software users to process data.

GPS/BDS组合导航系统的精密单点定位模型

为了改善单卫星导航系统由于卫星数量较少,导致定位误差高的问题,设计全球定位系统(GPS)/北斗卫星导航系统(BDS)组合导航系统的精密单点定位模型:线性组合处理GPS与BDS的伪距和载波相位观测值,并构建GPS/BDS组合导航系统的组合观测值;接下来利用协方差成形自适应卡尔曼滤波方法,对组合导航系统导航过程中的卫星钟差、电离层延迟等误差实施滤波;再利用滤波处理后组合导航系统的广播星历,获取卫星轨道以及钟差;然后利用经验模型修正对流层延迟,获取相位观测值与伪距的综合改正数;最后利用综合改正数修正组合导航系统的观测方程,构建精密单点定位模型。实验结果表明,GPS/BDS组合导航系统采用所构建模型进行精密单点定位,不同方向定位误差均低于10 cm,证明了提出模型的有效性。

GPS PPP技术用于滑坡监测的试验与结果分析

为了研究全球定位系统(GPS)精密单点定位(PPP)技术用于滑坡等地质灾害监测时可能达到的精度和可靠性等问题,结合某类滑坡的大型物理模型试验,在滑坡体上布设了若干GPS监测点进行连续实时动态监测,利用PPP技术对该滑坡从稳定、开始滑动直至产生破坏的全过程监测数据进行了处理与分析,并与GPS单历元差分定位、载波相位实时差分定位技术监测结果进行了对比。结果表明:GPS PPP技术监测结果的内符合精度约为10 mm,外符合精度约为40 mm,且GPS PPP技术具有一些差分GPS无法比拟的优势,如无需基准站支持、作业成本低、效率高、可直接获取监测点在国际地球参考框架下的绝对坐标等。该技术完全可用于滑坡等地质灾害的实时动态监测和预警。

高精度BDS+GPS变形监测技术在特高压线路地质灾害监测中的应用

BDS+GPS变形监测技术对特高压线输电杆塔的高精度监测具有重要意义。本文在构建BDS+GPS高精度定位数学模型的基础上,依据前后历元的一致性,给出稳健的GNSS观测数据预处理策略;兼顾监测算法的高精度及快速响应,利用实时滑动窗口时段解的解算策略对高压线输电杆塔的位移变化进行实时监测;采用B/C架构研发BDS+GPS变形监测软件,具有数据采集、数据解析、数据解算和前端展示功能。精密导轨试验结果表明,该算法的水平RMS小于3 mm,高程RMS小于5 mm,满足厘米级、毫米级变形监测需求。

基于精密单点定位技术的GPS辅助空中三角测量

简要介绍GPS精密单点定位的基本原理,通过对带双频动态GPS数据的1∶2 500~1∶60 000各种摄影比例尺的覆盖多种地形航摄资料的处理,比较了GPS精密单点定位与差分GPS定位所获取摄站坐标的差异,并分析利用两种摄站坐标分别进行GPS辅助光束法区域网平差的精度。试验表明,当区域四角布设四个平高地面控制点时,两者的加密精度是基本一致的,且采用GPS精密单点定位技术进行GPS辅助空中三角测量结果能够满足我国现行航空摄影测量规范的精度要求。

GPS-RTK技术在地籍测量中的实践应用探讨

主要探讨GPS-RTK技术在地籍测量中的应用。阐述了RTK技术的基本原理、测量方法和质量控制方法,并结合地籍测量的具体实例,在导线测量和高程测量方面,将RTK技术与全站仪进行对比,对平面和高程精度进行分析。结果表明,RTK用于地籍测量其精度完全能达到地籍测绘的要求。该技术用于地籍测量切实可行,值得推广和应用;同时总结了RTK技术在地籍测量中的优势和不足,在实际应用中应注意的事项等,可供同行参考。

无水准数据的GPS高程转换方法及精度分析

研究利用GPS精密点定位技术并联合相对定位技术,确定地面点在WGS84坐标系下的大地坐标,并直接用EGM2008模型进行高程转换。基于4个IGS站数据分析了不同观测时间长度精密点定位的解算精度,并通过两个工程实例数据对GPS高程转换方法的精度进行分析,结果显示:在华北和华南某些地区,用EGM2008模型直接进行高程转换,其精度有望达到15cm。

GPS技术在贵南高速铁路竣工测量中的应用

全球定位系统(Global Position System,GPS)技术凭借精准定位、实时监测、数据记录与分析等优势,在贵南高速铁路建设中发挥着关键作用,成为不可缺少的工具。竣工图是高速铁路建设的重要资料。随着现代经济社会的发展,越来越多的高速铁路项目正在建设中,竣工图作为对高速铁路进行验收、运营、维护和改造的可靠依据,在整个工程中起着至关重要的作用。通过对贵南高速铁路(贵州段)竣工图的测量,重点探讨GPS技术在贵南高速铁路竣工测量中GPS的控制网布设、观测及后期数据处理和平差计算等内容。

高压输电线对GPS静态测量的影响

对高压线下GPS测量数据进行对比分析 ,得到高压输电线对GPS测量成果影响的定性结论 :对于高压线下精度不高的定位测量 ,GPS定位技术是可以胜任的。

GPS两种广播星历参数拟合及外推精度分析

给出了GPS系统现有导航电文与现代化后导航电文的参数拟合算法,比较分析采用两种不同广播星历参数进行轨道拟合与外推的精度。结果表明,在相同拟合时长下,18参数算法拟合精度高出16参数近一个数量级,外推2小时卫星轨道计算时,18参数算法优于16参数。参照目前的GPS广播星历更新策略,采用16参数4小时轨道拟合,误差损失约为14cm,采用18参数3小时轨道拟合,误差损失约为1cm。