长基线GPS数据处理和精度分析

通过对实例的计算和分析,论述了用ＧＰＳ商用软件可处理上百公里的基线数据,其精度满足仪器标称精度的要求。并论述了在短、中、长基线采用精密星历和广播星历进行数据处理的精度差别;对ＧＰＳ数据处理进行了有益的探索。     

浅谈GPS建立精密工程控制网、广播星历误差对相对定位精度的影响

通过某厂二种常规方法获得的成果与GPS网分别用广播星历（随机商用软件）、精密星历（精密软件）处理采集数据获得成果对比,研究GPS定位技术建立精密控制网和广播星历（随机软件）误差对相对定位精度的影响。     

GPS伪距双差方法比较分析

在文献[1]研究的理论背景下,研究将文献[1]中方法运用于GPS控制网中时需要解决的关键问题-获取基线偏差小于0.7m的基线初始值。为此,对简单伪距双差,精密星历伪距双差和载波相位平滑伪距双差进行了分析。用自编软件解算了实测基线,得出3种方法在15min时间内都可以获得偏差小于0.7m的基线向量初始值,其中载波相位平滑伪距双差的结果最理想。     

北斗/GPS融合静态相对定位用于高精度地面沉降监测的试验与结果分析

我国的北斗卫星导航系统(BeiDou Navigation Satellite System,缩写为BDS)已于2012年12月27日正式对亚太大部分地区提供连续无源定位、导航和授时服务.为了探讨BDS/GPS融合观测数据用于高精度地面沉降监测的效果和精度情况,利用5台兼容BDS和GPS系统信号的GNSS接收机,对西安市地面沉降GPS监测网中的9个监测点进行了复测.通过对连续观测10h以上4个时段观测数据的处理和分析,结果表明,相对于单独采用GPS观测数据进行基线解算而言,融合了BDS和GPS观测数据基线结果的内符合精度大大提高,水平方向的平均中误差从5mm改善至3mm,垂直方向的平均中误差从17mm 改善至12mm; 同时,监测结果的外符合精度也大大增强,X、Y、Z方向的平均中误差分别从6mm、15mm、10mm改善至1.5mm、8mm、5mm.这说明融合了BDS观测数据的BDS/GPS静态相对定位可以明显提高高精度地面沉降监测结果的内外符合精度.     

GPS技术在鸳鸯湖矿区的应用

鸳鸯湖矿区位于宁夏回族自治区宁东煤田,该次GPS作业利用3个三等三角点作为起算数据,2个四等三角点作为检核数据,进行网平差及高程拟合。外业数据质量检验结果表明其重复基线及同、异步环闭合差均小于限差,符合规范要求。内业数据处理采用广播星历网基线处理,无约束平差、约束平差基线分量改正绝对值均小于限差值。6个水准点的网平差高程拟合结果证实GPS高程精度优于三角高程。测量成果经宁夏测绘产品质量监督检查站检查,成果精度达到《全球定位系统（GPS）测量规范》（GB/T18314-2001）的有关精度要求。说明鸳鸯湖矿区清水营井田GPS控制网的成果可靠。     

权的确定方法在核电施工控制测量中的应用探讨

在精密工程测量中,确定非同类观测值之间权的正确比例关系,对提高平差成果的质量具有重要意义。针对核电施工控制测量中,普遍采用高精度全站仪建立边角网、测量数据平差处理时按经验定权的现状,将Helmert验后方差定权引入核电测量数据处理,结合实际工程算例,阐明了二种定权方法之间的关系;克服了观测值先验精度与观测实际不符时定权不准确的不足;根据法方程及Helmert估算公式的特点,对工程中有效运用Helmert验后方差估计方法,进行了探讨。     

GNSS高精度数据处理方法与技术

GAMIT/GLOBK软件是国际上著名的高精度GNSS数据处理软件,通过它可以获得高精度基线解算解,为后续网平差获得高精度测站坐标打下重要基础。GAMIT/GLOBK软件在Linux或Unix系统通过命令运行,能熟练掌握操作和使用方法是进行高精度基线解算的前提。     

GAMIT与BERNESE在GPS基线解算中的比较

对高精度数据处理软件BERNESE和GAMIT进行了简单介绍,并用这两种后处理软件来处理长度大于1 000km的基线,对各种软件解算的结果进行了比对分析,得出两种软件在数据处理方法、精度、解算准确度等方面的差别,并对其使用条件提出了建议。     

城市CORS系统在地面沉降监测中的应用

采用国际上通用的GNSS高精度后处理软件GAMIT/GLOBK,对26个连续运行参考站的监测数据进行基线与平差解算.结果表明:CORS站解算结果大地高精度都在2 mm之内,其中有23个站的高程误差小于1 mm,占总数的88.5％,可以得到高精度解算成果.将部分已有的CORS站纳入地面沉降监测系统,可以弥补监测站的数量不...     

精密单点定位技术在青藏高原地区物探测量中的应用研究

精密单点定位技术具有无需控制点、单台GPS接收机静态测量可获得高精度的坐标成果等优点,在青藏高原等困难地区的物探测量实践中具有广阔的应用前景。本文以利用精密单点定位技术处理青藏高原西部和东部的两个1∶25万区域重力调查项目形成的控制点观测数据为基础,经过计算对比这些点的精密单点定位成果和传统测量平差方法所得的CGCS2000坐标成果之间的差值,分析误差来源,得出误差的主要来源是两者坐标值在历元和框架差异引起,进而通过历元和框架校正得出控制点的CGCS2000坐标,重新对比发现校正后的坐标值具有与传统测量平差坐标值相一致的精度,在此基础上提出了在实际物探测量中利用精密单点定位技术得到CGCS2000坐标成果的思路和注意事项,同时讨论了该方法的应用范围。     

GPS广播星历轨道误差试验研究

介绍了如何利用广播星历中的开普勒轨道参数和轨道摄动修正量计算GPS卫星轨道坐标的方法和步骤。编写了根据广播星历计算GPS卫星轨道坐标软件，并根据实际广播星历数据计算了GPS卫星轨道坐标，然后与同一历元的IGS精密星历所提供的每15min GPS卫星的坐标进行了比较，探讨其轨道误差，并得出了一些值得借鉴的结论。     

Multipath interference cancelation in GPS time series under changing physical conditions by means of adaptive filtering

Multipath, a highly autocorrelated signal is observable phenomena during time periods longer than the sidereal period of Global Positioning System (GPS) satellites in their constellations. Multipath pattern and sidereal repeat time interaction are examined in terms of time series correlations of topocentric coordinates using GPS code and phase observations collected at high and low frequencies. The horizontal and vertical components at 5 and 30 s sampling rates are analyzed to detect and remove multipath classified by their M P ₁ levels and baseline lengths. For the selected 11 stations that have 24-hour data from CORS stations in the USA and Turkey, the repeat times of the GPS constellation were identified as a function of maximum cross-correlation of adjacent time series. The multipath interference signal from two-day time series data is removed by an adaptive filter to improve time series of coordinate estimates. After the filtering process, an effective epoch based position tracking has been accomplished, especially in the height component. The position errors disappeared to maximum possible extent in the pseudo-range measurements. Up to 70% improvement for the phase derived coordinates in reflective environment has been achieved over the baselines ranging from 1 km to 175 km. For the phase observables, the filter success directly related to the multipath level which is specific to the station.     

Earth tide effects on kinematic/static GPS positioning in Denmark and Greenland

A detailed study of the Earth tide effects on the GPS kinematic/static positioning is presented in this paper by using theoretical Earth tide computation and practical GPS data processing. Tidal effects could reach up to 30 cm in Denmark and Greenland depending on the measuring time and the position of reference station. With a baseline less than 80 km, the difference of the Earth tide effects could reach more than 5 mm. So, in precise applications of GPS positioning, the Earth tide effect has to be taken into account even for a relative small local GPS network. Several examples are given for demonstrating that the Earth tide effects can be viewed by GPS surveying. They are given through static GPS data static processing, static GPS data kinematic processing, and airborne kinematic GPS data processing. In these cases, the Earth tide effects can be subtracted from the GPS results. The determination of tidal parameter through static GPS data kinematic processing has also been tested.     

Plate motion predictability using Hurst exponent applied to the Maitri-antarctica GPS network

The Global Positioning System (GPS) data collected during years 1997–2007 at Maitri along with the International GNSS Service (IGS) stations viz. Casey, Davis, Yaragadee, Tidbinbilla, Seychelles, Coco, Diego Garcia, Kerguelen and Hartbeesthoek in and around Indian Ocean were processed using Bernese. 4.2 software. The baseline length and their changes were estimated and spectral analysis was carried out subsequently. The value of the Hurst exponent, as estimated from the slope of spectral fall-off of each time series of baseline length, was used to interpret the characteristics of the plate motions in the region. The Hurst exponent is found to be 0.65 (>0.5) for the baseline length between stations Kerguelen and Coco clearly showing a constant increasing trend of the changes in baseline length. The time series of baseline lengths between stations Kerguelen and Diego Garcia; and Tidbinbilla and Yaragadee shows an increasing trend and the Hurst exponent is close to 0.5. This may suggest that the diffuse plate boundary zone and the Australian plate are moving away from the Antarctican plate. The baseline length between Kerguelen and Davis, Casey, Maitri and Seychelles is less than 0.5, which indicates that the baseline length of these stations shows a decreasing trend.     

天津市高精度GPS地面沉降监测网数据处理中的若干技术问题探讨

本文以天津市区地面沉降GPS监测网为例,探讨了高精度GPS地面沉降监测网数据处理中的若干技术问题。研究表明,GPS数据处理软件、GPS监测网的框架基准、大气延迟改正和粗差对计算结果的精度有很大影响。在对GPS原始观测数据进行后处理时,只有对影响计算精度的各种误差源进行有效改正,GPS高程分量的精度才有可能达到毫米级,才能满足地面沉降监测的要求。     

GPS在滑坡监测中的应用研究

本文主要介绍GPS用于地质灾害滑坡监测的技术和方法,并通过在中国四川雅安峡口滑坡示范区布设的GPS监测网的测量试验,阐述了在地形复杂、观测条件恶劣的山区进行GPS滑坡监测时,监测点位选择、监测网布设、数据处理的方法。监测结果表明,GPS滑坡监测的精度达到毫米级,完全可以应用于滑坡监测。      

Study the feasibility of using PPP for establishing CORS network

Nowadays many continuously operating reference stations (CORS) network were established in Middle East to improve the surveying tasks. Establishing such geodetic control networks can be a costly business where multiple stations should be occupied simultaneously and post-processed with scientific software. Recently, precise point positioning (PPP) provides precise positioning values that may be an alternative to precise relative processing. The current research aims to investigate that PPP has a potential as a reliable absolute positioning technique operational simplicity as well as to investigate the capability of PPP approach to be a low cost alternative to the conventional positioning methods used in position determination of core networks stations. In comparison with common relative GPS techniques, the costs are reduced; because no base stations and no simultaneous observations are necessary, no need for control network maintenance which could be the most defective factors that Egypt HARN network suffered from. To see the feasibility study of using PPP for precise determination of the CORS, 14 days of GNSS data for the 14 Kuwait integrated with 27 IGS stations were processed by Bernese software to calculate the precise coordinates of Kuwaiti CORS network in the latest terrestrial geodetic frame. Three days of these data were processed by Trimble business center software and using PPP approach to calculate the precise coordinates of Kuwait network. In the current research, a comparable investigation was carried out between the coordinates obtained from Bernese software, Trimble business center, and PPP approach. The comparison proved high level of agreement between the coordinates which confirm that PPP approach can be applied for establishment of CORS network.