GPS技术在气象学中的应用

ＧＰＳ技术的成熟使其成为对地观测的一种强有力的手段。ＧＰＳ技术在大气观测和全球气候变化监测中应用的可能性使得ＧＰＳ气象学（ＧＰＳ／ＭＥＴ）成为一个崭新的极有潜力的研究方向。本文对ＧＰＳ气象学及其分类作简单介绍之后,着重地阐述了ＧＰＳ气象学的基本原理和ＧＰＳ气象学的广阔应用领域。     

GPS网的网形结构对成果影响的探讨

本文通过对江阴市Ｄ、Ｅ（东部）级ＧＰＳ网和溧阳市Ｅ级ＧＰＳ网,选取不同的观测基线向量,以构成不同的网形,分别进行无约束平差,比较分析各种网形的平差结果,从而得出较为经济、成果可靠、精度良好的ＧＰＳ网形,来指导生产实践。     

GPS短边网精度的研究

《ＧＰＳ测量规范》规定了ＧＰＳ测量的等级及各级ＧＰＳ网相邻点间距离,最低级Ｅ级网相邻点间距为１～１０ｋｍ,平均边长为２～５ｋｍ。根据工程的要求,有时控制网相邻点间距仅为几十至几百米,文中针对ＧＰＳ短边网的数据处理和精度进行分析,并对ＧＰＳ网的质量检核进探讨,采用全站仪对网进行检核发现ＧＰＳ边长误差在５ｍｍ以内。     

北斗卫星载波动态差分定位最新性能评估

为了评估ＢＤＳ载波动态差分的最新定位性能,文中选择在巴西、美国、澳大利亚和中国境内共８个ＩＧＳ站构 成的基线长度在３０ｋｍ以下的４条基线,基于２０２１－１０－０８—２０２１－０８－１４ＢＤＳ,ＧＰＳ以及ＢＤＳ＋ＧＰＳ观测数据进行载 波动态差分定位,统计并分析可见卫星数目、ＥＮＵ 时间序列和定位精度,获得了ＢＤＳ最新的载波动态差分定位性 能。结果表明,ＢＤＳ可见卫星数明显多于ＧＰＳ;ＢＤＳ与ＧＰＳ载波动态差分定位结果稳定性基本相同;ＢＤＳ与ＧＰＳ载 波动态差分定位精度在Ｅ,Ｎ,Ｕ方向均能达到ｃｍ级精度,且在Ｅ和Ｎ方向的定位精度优于１ｃｍ。与单系统相比, ＢＤＳ与ＧＰＳ的组合系统能较好地提高定位精度。     

ASHTECH GPS接收机在施测作业中出现故障的应急处理

ＧＰＳ野外施测中，由于各种意外因素的干扰，使仪器无法正常工作，影响到ＧＰＳ野外作业的实施计划，本文针对这个问题，根据笔者多年野外作业的工作经验，介绍了ＡＳＨＴＥＣＨ ＧＰＳ接收机在野了测中常见仪器故障可采取的应急处理措施。     

用差分GPS采集1：5万公路数据的技术关键—兼述全国铁路数据采集的？…

讨论了利用差分ＧＰＳ技术进行１：５万国家空间基础地理信息公路层数据采集中遇到的几个问题和解决方法,对１：５万国家空间基础地理信息铁路层数据采集提出了利用ＩＮＴＥＲＮＥＴ网络中的ＧＰＳ精密星历和星钏差等资源进行事后单机定位－事后广域差分的技术设想。     

G ＆ E快速测图系统的研制

Ｇ ＆ Ｅ快速测图系统是ＧＰＳ技术与全站仪技术的集成。本文介绍了Ｇ ＆ Ｅ快速测图系统的原理与工作过程。     

GPS接收机性能评述

本文阐述ＧＰＳ接收机的分类和各种机型的性能，技术指标和参考价格，同时介绍了当前各类ＧＰＳ接收机的特点和工作模式，并对窄距相关技术，ＭＥＴ－ＭＥＤＬＬ技术，Ｐ－Ｗ跟踪技术作了简要介绍，文后的用户根据经费，任务特点，精度要求，选择机型提出了自己的看法。     

全球定位系统（GPS）及其在高等级道路勘测中的应用

全球定位系统（ＧＰＳ）及其在高等级道路勘测中的应用ＧＬＯＢＡＬＰＯＳＩＴＩＯＮＩＮＧＳＹＳＴＥＭ（ＧＰＳ）ＡＮＤＩＴＳＡＰＰＬＩＣＡＴＩＯＮＴＯＨＩＧＨ－ＧＲＡＤＥＲＯＡＤＲＥＣＯＮＮＡＩＳＳＡＮＣＥＳＵＲＶＥＹ姚连璧（同济大学测量与国土信息工程系,...     

区域性跟踪站地心坐标精化方法及定轨试验分析：中国GIG‘91和IGS’92会战数？

本文了中国ＧＩＧ’９１和Ｅｐｏｃｈ’９２二次ＧＰＳ会战的情况,着重分析了ＧＩＧ’９２和Ｅｐｏｃｈ’９２会战数据处理的结果。     

GPS/BD组合导航定位试验和精度分析

讨论了GPS/BD组合定位需要考虑的主要问题,自编了GPS/BD组合定位程序,利用实测GPS/BD观测数据分析了当前北斗导航定位系统可用性及GPS/BD组合前后的定位精度。试验结果表明,北斗已经能够提供区域的实时导航定位服务。GPS/BD组合定位在GPS观测卫星数较多时对GPS定位精度改善不明显,在GPS观测卫星数较少时可以显著提高定位精度和稳定性。     

GPS单点测速的误差分析及精度评价 (英文)

Error sources which decrease the accuracy of GPS in absolute velocity determination have been changed since SA was turned off. Firstly, quantities of all kinds of error sources that influence velocity determination are analyzed. The potential accuracy of GPS absolute velocity determination is derived from both theory and field GPS data simulation. After that, two tests were carried out to evaluate the performance of GPS absolute velocity determination in the case of a static and an airborne GPS receiver and INS （Inertial Navigation System） instrument in kinematic mode. In static mode, the receiver velocity has been estimated to be several mm/s with the carrier-phase derived Doppler measurements, and several cm/s with the receiver generated Doppler measurements. In kinematic mode, GPS absolute velocity estimates are compared with the synchronized measurements from the high accuracy INS. The root mean square statistics of the velocity discrepancies between GPS and INS come up to dm/s. Moreover, it has a strong correlation with the acceleration or jerk of the aircraft.     

关于GPS高程测量精度的分析比较

近年来,GPS技术得到了广泛的应用,但是科学数据表明,GPS高程测量精度还受到一些因素的影响,因此,限制了GPS测量功能的发挥。为了使GPS高程测量在实际中得到更加广泛的应用,本文对GPS高程测量的基本原理和影响因素进行了分析,经过比较,重点研究如何提高GPS高程测量精度。     

Denoising effect of multiscale multiway analysis on high-rate GPS observations

GPS Solutions - In general, high-rate GPS data sets are subject to common mode error (CME), multipath error, and high-frequency random noise, which adversely affect the GPS positioning accuracy. In...     

浅析2010年度GPS升级调整对用户的影响

2010年1月份,美国对GPS系统进行了升级调整,部分用户受到影响。通过对GPS工作原理和信号特点的分析,对照实测GPS信号导航电文的变化,分析了这次调整可能对用户造成影响的机理。最后,对这次调整可能给用户带来的实际影响作了判断。     

GPS卫星坐标的计算

GPS卫星的坐标计算是利用GPS进行定位的关键环节，在利用GPS进行导航和测量时，需要多次计算卫星的坐标，因此快速准确地计算出卫星任意时刻的坐标，对于提高GPS定位精度和速度具有重要的意义。通过实例分析了利用广播星历的轨道参数、拉格朗日多项式插值和切比雪夫多项式拟合这三种方法计算卫星任意时刻的坐标，并进行了精度比较。     

The application of GPS precise point positioning technology in aerial triangulation

In traditional GPS-supported aerotriangulation, differential GPS (DGPS) positioning technology is used to determine the 3-dimensional coordinates of the perspective centers at exposure time with an accuracy of centimeter to decimeter level. This method can significantly reduce the number of ground control points (GCPs). However, the establishment of GPS reference stations for DGPS positioning is not only labor-intensive and costly, but also increases the implementation difficulty of aerial photography. This paper proposes aerial triangulation supported with GPS precise point positioning (PPP) as a way to avoid the use of the GPS reference stations and simplify the work of aerial photography.Firstly, we present the algorithm for GPS PPP in aerial triangulation applications. Secondly, the error law of the coordinate of perspective centers determined using GPS PPP is analyzed. Thirdly, based on GPS PPP and aerial triangulation software self-developed by the authors, four sets of actual aerial images taken from surveying and mapping projects, different in both terrain and photographic scale, are given as experimental models. The four sets of actual data were taken over a flat region at a scale of 1:2500, a mountainous region at a scale of 1:3000, a high mountainous region at a scale of 1:32000 and an upland region at a scale of 1:60000 respectively. In these experiments, the GPS PPP results were compared with results obtained through DGPS positioning and traditional bundle block adjustment. In this way, the empirical positioning accuracy of GPS PPP in aerial triangulation can be estimated. Finally, the results of bundle block adjustment with airborne GPS controls from GPS PPP are analyzed in detail.The empirical results show that GPS PPP applied in aerial triangulation has a systematic error of half-meter level and a stochastic error within a few decimeters. However, if a suitable adjustment solution is adopted, the systematic error can be eliminated in GPS-supported bundle block adjustment. When four full GCPs are emplaced in the corners of the adjustment block, then the systematic error is compensated using a set of independent unknown parameters for each strip, the final result of the bundle block adjustment with airborne GPS controls from PPP is the same as that of bundle block adjustment with airborne GPS controls from DGPS. Although the accuracy of the former is a little lower than that of traditional bundle block adjustment with dense GCPs, it can still satisfy the accuracy requirement of photogrammetric point determination for topographic mapping at many scales.     

A comparison of GPS, VLBI and model estimates of ocean tide loading displacements

In recent years, ocean tide loading displacements (OTLD) have been measured using the Global Positioning System (GPS) and Very Long Baseline Interferometry (VLBI). This study assesses the accuracy of GPS measurements of OTLD by comparison with VLBI measurements and estimates derived from numerical ocean tide models. A daily precise point positioning (PPP) analysis was carried out on ∼11 years of GPS data for each of 25 sites that have previous OTLD estimates based on data from co-located VLBI sites. Ambiguities were fixed to integer values where possible. The resulting daily estimates of OTLD, at eight principal diurnal and semi-diurnal tidal frequencies, were combined to give GPS measurements of OTLD at each site. The 3D GPS and VLBI measurements of OTLD were compared with estimates computed (by convolution with Green’s functions) from five modern ocean tide models (CSR4.0, FES2004, GOT00.2, NAO99b and TPXO6.2). The GPS/model agreement is shown to be similar to the VLBI/model agreement. In the important radial direction, the GPS/model misfit is shown to be smaller than the VLBI/model misfit for seven of the eight tidal constituents; the exception being the K2 constituent. Fixing of GPS carrier-phase ambiguities to integer values resulted in a marginal improvement to the GPS/model agreement. Statistically, it is shown there is no significance to the difference between the fit of the GPS and VLBI measurements of OTLD to modelled values. Equally, differences in fit of either the complete set of GPS or VLBI estimates to the five sets of model-derived values cannot be identified with statistical significance. It is thus concluded that, overall, we cannot distinguish between GPS and VLBI measurements of OTLD, and that at the global scale, present ocean tide models are accurate to within the current measurement noise of these techniques.     

GPS和地球动力学进展

在 2 0 0 3年 7月日本举行的第 2 3届IUGG大会上 ,全球大地测量领域的专家和学者对GPS的技术改进和应用、GPS及其地球动力学应用方面等做了较为系统的交流。本文对这次会议中有关GPS及其地球动力学领域的最新研究成果及大地测量数据处理的最新进展做简要介绍     

利用卫星高度角和信噪比提高GPS定位精度的试验分析

GPS基线解算通常基于观测值独立且同精度的假设建立等权随机模型,在复杂环境下采用该模型往往无法满足高精度的定位要求。文中从研究卫星高度角、信噪比与GPS观测值质量之间的关系出发,利用卫星高度角、信噪比信息分别建立相应的精密随机模型。通过对试验结果分析对比,验证了基于卫星高度角和信噪比的随机模型的可靠性和其提高GPS定位精度的有效性。