浅谈GPS技术在"竿影日照图"测量中的应用

按照规划原理的要求,利用GPS定位技术测定本地区“竿影日照图”,用以规范和指导城市规划中建筑物、构筑物等的日照间距问题,同时对GPS观测中的体会加以总结。     

Atmospheric turbulence theory applied to GPS carrier-phase data

Turbulent irregularities in the lower atmosphere cause physical correlations between Global Positioning System (GPS) carrier-phase measurements. Based on turbulence theory, a variance–covariance model is developed in this paper that reflects these correlations. The main result shows that the obtained fully-populated variance–covariance matrices depend not only on the satellite-station geometry, but also on the prevailing atmospheric conditions, which are parameterised by, e.g., the von Karman spectrum of refractivity fluctuations and the wind velocity vector. It is shown that the amount of the correlation between two GPS carrier-phase observations is inversely related to the separation distance of the corresponding ray paths through the turbulent atmosphere. Furthermore, the wind velocity and direction play a key role in the correlation.     

GPS动态定位中LAMBDA算法的分析及验证

利用载波相位观测量进行GPS动态定位的关键技术是模糊度的动态确定（AROF）,模糊度解算的实时性和可靠性是AROF研究的热点和难点。深入研究LAMBDA算法的原理和方法,并用实例解算进行分析,验证LAMBDA算法对模糊度求解的快速、准确和可靠,具有很好的实用价值。     

一个用于GPS数据操作的实用软件

介绍了一个简单实用的GPS工具软件，描述了针对不同型号的接收机，可以完成数据的标准RINEX格式转换、数据质量检查和编辑工作，尤其数据质量检查的结果对了解接收机性能和数据环境等具有一定的指导作用。     

小波技术在GPS基线解算数据预处理中的应用

采用小波技术对GPS观测数据进行处理。应用小波变换技术对GPS相位观测值进行周跳的探测和修复。GPS相位观测值可以作为时间序列来进行分析,作为时间函数,它所表现出来的是一条光滑度很好的曲线,一旦出现周跳,这种光滑性就被破坏,从发生周跳的历元开始,后继相位观测值序列发生等量阶跃,通过小波变换的信号特性检测原理,能够有效地探测出周跳的发生,这种方法对于缩小模糊度搜索空间及提高模糊度解的有效性有明显的作用,从而提高基线解算的精度。     

The confidence evaluation for airborne GPS data

l lntroductionIn the winter Of l989 Wuhan Technical Universi-ty of Surveying and Mapping COntracted withTrimble Navigation Ltd. to purchase fOur TrimbIe4000SST receivers. They were required tO suit theaeriaI phWetric work without intreducing avelocity limitation. In February, l993 twO of thereceivers were uPgraded to provide two eventrnarker plugfords and one pulse Per second(lPPS) output axkets. The uPgradd receivers canincormrate external event markers, e. g. the shutter.oPening …     

一种检验GPS整周模糊度解算有效性的方法

检验解算的整周模糊度是GPS精密快速定位的一个重要课题。过去已提出了不少方法,然而这些方法都存在一定的缺陷。本文提出一种新的方法,它是基于模型可区分度的概念。该方法利用可接受的第一、二类错误概率,计算边界值,并与固定解中最小残差二次型和次最小残差二次型比较,以确认相应于最小残差二次型的整周模糊度的有效性。     

浅析GPS在高速公路测量中的优势

简述了GPS测量技术的原理,列出了GPS用于测量的特点,结合其特点,比较GPS测量与常规测量在公路测量中的优劣。GPS用于高速公路测量是完全可行的,它在很大程度上可以提高测量的工作效率。     

GPS天线相位模型变化对高精度GPS测量解算的影响研究

GPS天线存在相位中心偏差,在高精度测量中必须对其进行补偿改正。本文针对GPS天线的两种改正模型:相对改正模型和绝对改正模型,在讨论了它们所具有的相同改正办法的基础上,分析了它们在测定方法上存在区别,最后通过一个算例分别研究了这两种模型对GPS测量解算精度的影响,得出了一些有意义的结论。     

基于LabView的GPS数据采集及处理

首先介绍全球定位系统(GPS)的基本工作原理及其通常所采用的通信协议,然后阐述了基于LabView的GPS串口数据采集及处理程序的设计思路和主要功能,最后程序实现了对GPS定位信息的采集、存储及对定位信息的实时显示。     

GPS控制网图形应用程序的类设计

根据对基线数据的特点分析,运用面向对象的编程方法,对GPS控制网图形应用程序进行了类设计,包括类层次划分、各类的数据成员及其函数的设计。基于类开发的GPS控制网图形应用程序,实现了对基线数据及其操作的封装,有利于程序对基线数据的处理。同时,利用父类与子类间数据成员、成员函数的继承关系,可以优化GPS控制网图形应用程序的整体设计。     

Minimal detectable biases of GPS data

In this contribution closed-form expressions are given for the minimal detectable biases of single- and dual-frequency pseudo-range and carrier-phase data. They are given for three different single-baseline models. These are the geometry-free model and two variants of the geometry-based model, namely the roving and stationary variants. The baselines are considered to be sufficiently short such that orbital uncertainties in the fixed orbits and residual ionospheric and tropospheric delays can be assumed absent. The stochastic model used is one that permits cross-correlation and the use of different variances for individual GPS observables, including the possibility to weigh the observables in dependence on which satellite is tracked. Received: 23 April 1997 / Accepted: 27 October 1997     

由星载GPS相位数据确定地球重力场模型若干问题研究

人造地球卫星在地球引力场中运动,可以探测地球重力场的长波信息。随着GPS技术的发展,星载GPS技术日趋成熟,因此由星载GPS相位数据确定地球重力场模型是当前国际地学研究的热点之一。本文给出了确定地球重力场模型中的星载GPS星地相位双差观测量,阐述了Cowell II数值轨道积分公式,导出了参数估计中星地双差观测量的偏导数,利用分块Bayes最小二乘参数估计地球引力场位系数等有关参数。     

卡尔曼滤波在GPS数据预处理中的应用

为了提高GPS数据预处理过程中基线解算的精度,文章研究利用多项式拟合法得到Kalman滤波的系统状态方程和转移矩阵,提出利用Kalman滤波算法对三差观测值进行粗差及周跳的修复。实验结果证明Kalman滤波可以对含噪信号进行有效的降噪,经降噪后的信号具有更好的分布。     

Generation and validation of DEM using SAR interferometry and differential GPS supported by multispectral optical data

Digital elevation model (DEM) and the derived terrain parameters e.g. contour, slope, aspect, drainage pattern, etc are required for natural resources management, infrastructure planning and disaster management. The present paper aims at generating DEM from ERS tandem pair using interferometric technique supported by differential GPS measurements (DGPS) and multispectral optical data. Validation of DEM has been carried out by DGPS measurements. Ground Control Points (GCP) established by DGPS measurements have been used to georeference the IRS-1D optical data that has finally been co-registered with SAR amplitude image. Optical data, co-registered with ERS - I SAR data has helped in locating the GCP’s and check points, precisely, for refinement of DEM and its validation.     

GPS跟踪站数据管理业务自动化建设

在简单介绍国家测绘局GPS跟踪站管理模式的基础上．介绍国家测绘局GPS数据中心自动化的跟踪站数据管理业务系统的组成，介绍了自主开发研制的GPS跟踪站数据管理业务软件(GDS-AUTO)的功能模块、特点。     

Applications of graph theory to gross error detection for GPS geodetic control networks

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Applications of graph theory to gross error detection for GPS geodetic control networks

This paper describes a broad perspective of the application of graph theory to establishment of GPS control networks whereby the GPS network is considered as a connected and directed graph with three components. In this algorithm the gross error detection is undertaken through loops of different spanning trees using the “Loop Law” in which the individual components ΔX, ΔY and ΔZ sum up to zero. If the sum of the respective vector components ΩX, ΩY and ΩZ in a loop is not zero and if the error is beyond the tolerable limit (ε>ω), it indicates the existence of gross errors in one of the baselines in the loop and therefore the baseline must be removed or re-observed. After successful screening of errors by graph theory, network adjustment can be carried out. In this paper, the GPS data from the control network established as refence system for the HP Dam at Baishan county in Liaoning province is presented to illustrate the algorithm.     

单频GPS非连续历元周跳处理研究

常规的周跳处理方法大都适用于连续观测数据中的周跳处理,本文则重点针对由于建筑物遮挡或信号干扰等原因,暂时性中断的GPS数据可能出现的周跳进行正确处理的研究。本文采用基于模糊度参数重设的GPS定位模型重建以及基于变采样区间的改进的多项式拟合法的周跳处理算法,可在一定程度上有效解决GPS数据失锁对于定位解算造成的不利影响。     

A data archive of GPS navigation messages

Since 18 June 2007 navigation data messages transmitted by the GPS constellation are recorded by five receivers within GeoForschungsZentrum’s global groundstation network. We describe the recording, processing, validation, analysis and archiving of the navigation data. During the 197 days between 18 June 2007 and 31 December 2007 a total of 125,723,666 subframes were collected. By taking into consideration that the same data set frequently is observed by two or more receivers concurrently, 65,153,955 unique subframes could be extracted from the observations. With an estimated 88,099,200 subframes transmitted by the constellation during this time period a data yield of about 74% was achieved. Simulation studies suggest that with two additional GPS receivers, which are scheduled for addition to the network in 2008, about 95% of the transmitted subframes will be retrieved. The message data archive is open to the scientific community for non-commercial purposes and may be accessed through GFZ’s Information System and Data Center ().