共查询到20条相似文献,搜索用时 328 毫秒
1.
长距离网络RTK是实现GPS/BDS高精度实时定位的主要手段之一,其核心是长距离参考站网GPS/BDS整周模糊度的快速准确确定。本文提出了一种长距离GPS/BDS参考站网载波相位整周模糊度解算方法,首先利用GPS双频观测数据计算和确定宽巷整周模糊度,同时利用BDS的B2、B3频率观测值确定超宽巷整周模糊度。然后建立GPS载波相位整周模糊度和大气延迟误差的参数估计模型,附加双差宽巷整周模糊度的约束,解算双差载波相位整周模糊度,并建立参考站网大气延迟误差的空间相关模型。根据B2、B3频率的超宽巷整周模糊度建立包含大气误差参数的载波相位整周模糊度解算模型,利用大气延迟误差空间相关模型约束BDS双差载波相位整周模糊度的解算。克服了传统的使用无电离层组合值解算整周模糊度的不利影响。采用实测长距离CORS网GPS、BDS多频观测数据进行算法验证,试验结果证明该方法可实现长距离参考站网GPS/BDS载波相位整周模糊度的准确固定。 相似文献
2.
3.
利用普通Kriging插值的指数函数模型和高斯函数模型,精密地实时估计网络RTK中用户站每一历元的大气延迟。利用一个含6个参考站的GPS网络(参考站间距为38.8~132.7km)的观测数据进行了实验,结果表明,对于长度为79.1km的基线的双差电离层延迟和双差对流层延迟,相应的Kriging插值(指数模型和高斯模型)的精度一般可达2cm和5cm,这表明普通Kriging插值可用于网络RTK用户站的大气延迟内插。 相似文献
4.
在InSAR大气延迟改正双差模型的基础上,推导了适用于三归法D-InSAR测量的大气延迟改正模型。利用新西兰GEONET北岛连续观测GPS数据,研究了多雨山区InSAR对流层延迟内插模型。 相似文献
5.
基于MODIS与GPS的D-InSAR大气延迟改正量提取 总被引:1,自引:0,他引:1
受GPS站点密度的限制,利用GPS数据改正D-InSAR中大气延迟误差往往达不到很好的效果。为此,研究了GPS与MODIS联合实现大气延迟改正量提取方法,利用两期GPS观测数据及相应时间的MODIS数据分析GPS-PWV与MODIS-PWV的关系,进一步得到MODIS水汽的校正模型。经过GPS+MODIS算法改正后,大气延迟改正精度为3.618mm,满足形变测量的要求。实验结果表明:在大气状态变化缓慢时,利用GPS结合MODIS数据对D-InSAR大气延迟改正有一定的效果。 相似文献
6.
7.
8.
高精度GPS网的统一与数据处理若干问题研究 总被引:4,自引:0,他引:4
我国自20世纪90年代初开始,由不同部门先后建成了全国GPS一级网和二级网、国家GPS A级网和B级网、中国地壳运动观测网络、以及全国GPS地壳运动监测网和区域地壳形变监测网等.分布全国除台湾省以外的陆地和岛屿,总计2 400多点. 对于我国早期布测的各个GPS网,由于观测时刻卫星星座和星历的不完善,接收机的精度偏低,且由于财力不足,同步观测仪器少,各单位不得不分期观测、分级观测、分区观测.由于上述因素的影响,致使各个GPS网的兼容性很差;在标定基准方面,并不具备全球背景,各个子网存在着明显的系统差和基准定义差;资料零乱,信息不能共享,使用效率低,造成极大的资源浪费.为了能充分利用现有各个GPS网,使其发挥整体效益,特别是利用网络工程基准站和基本站的高精度观测信息提高现有GPS网的精度,维持大地测量动态坐标框架,更好地为国家的经济建设和国防建设服务,对这些高精度GPS网的联测和观测资料的联合处理进行研究非常必要.本文的主要研究内容如下: 1.提出了全国GPS网与中国地壳运动观测网络联测的设计思想.完成了全国GPS一、二级网与中国地壳运动观测网络联测的技术设计方案,并用于实际联测. 2.系统地讨论了高精度GPS网数据处理的平差方法及其对应基准的意义,提出了基于Bayes理论的GPS数据处理方法,推导了相应的参数估值公式及其验后协方差估值公式,推导了基于不同基准、不同历元平差结果的转换公式. 3.详细研究了GPS数据处理中基准站的选取、基准站坐标的约束等问题,首次系统地讨论了基准站选取的几何意义、统计意义与物理意义,提出了基准站选取的一般原则. 4.建立了同时顾及坐标框架系统参数和地壳运动参数的GPS网联合平差模型.使用该模型可使块体的运动参数与全网的坐标转换参数相分离,从而提高所求坐标转换参数的精度和可靠性,并用多组GPS实测数据验证了所建模型的正确性和可靠性. 5.利用国内多个GPS网的联测数据分析了中国大陆现今构造块体的相对运动特征,讨论了相应的应变场,为研究我国的大地构造及地球动力学提供了重要的约束. 6.将抗差估计理论用于地壳运动应变场的分析,推证了应变参数的抗差估计解式,以及观测误差对各类解的误差影响函数和解差函数,分析了观测异常对应变参数解的影响. 相似文献
9.
基于GPS的InSAR干涉图大气效应校正方法研究 总被引:1,自引:0,他引:1
大气折射延迟是InSAR测量的一个重要误差源,严重影响对干涉图的正确解译,因此必须对其进行削弱或消除,利用GPS连续运行站估计的大气天顶延迟可对干涉图中的大气效应进行校正.但离散的GPS天顶延迟须进行空间插值才能满足InSAR的高分辨率要求.本文基于天津的GPS观测数据,利用Berense、PANDA软件估算了天顶延迟... 相似文献
10.
BDS-3通过其高轨道卫星的B2b信号向亚太地区用户免费提供了标准精密单点定位服务,但PPP近半小时的收敛时间和分米级的实时定位精度不利于其后续应用推广。因此,本文提出了融合PPP-B2b精密卫星轨道产品与区域稀疏参考站观测数据的增强定位方法,即基于PPP-B2b的非差非组合精密单点实时动态定位技术,并采用站间单差电离层伪观测值对其进行约束,以实现电离层延迟等参数的严密估计。此外,本文还重点设计了区域电离层斜延迟及其精度信息的单星实时建模方案,有效压缩播发数据量的同时提高了PPP-RTK的应用性能。在此基础上,利用京津区域参考网对上述方法进行了近实时验证。结果表明:本文方法提供的电离层斜延迟修正精度可达2.2 cm(BDS-3)/2.4 cm(GPS);超95%BDS-3+GPS定位样本的绝对误差可在2 s内收敛到水平2 cm与垂直5 cm,而且定位误差收敛后可实现水平毫米级与垂直厘米级的定位精度。 相似文献
11.
Quality assessment of GPS rapid static positioning with weighted ionospheric parameters in generalized least squares 总被引:3,自引:2,他引:1
Pawel Wielgosz 《GPS Solutions》2011,15(2):89-99
Precise GPS positioning requires the processing of carrier-phase observations and fixing integer ambiguities. With increasing
distance between receivers, ambiguity fixing becomes more difficult because ionospheric and tropospheric effects do not cancel
sufficiently in double differencing. A popular procedure in static positioning is to increase the length of the observing
session and/or to apply atmospheric (ionospheric) models and corrections. We investigate the methodology for GPS rapid static
positioning that requires just a few minutes of dual-frequency GPS observations for medium-length baselines. Ionospheric corrections
are not required, but the ionospheric delays are treated as pseudo-observations having a priori values and respective weights.
The tropospheric delays are reduced by using well-established troposphere models, and satellite orbital and clock errors are
eliminated by using IGS rapid products. Several numerical tests based on actual GPS data are presented. It is shown that the
proposed methodology is suitable for rapid static positioning within 50–70 km from the closest reference network station and
that centimeter-level precision in positioning is feasible when using just 1 min of dual-frequency GPS data. 相似文献
12.
Real-time precise point positioning regional augmentation for large GPS reference networks 总被引:6,自引:1,他引:5
An increasing number of GNSS reference stations are installed around the world to provide real-time precise positioning services. In most of the current services, a full network solution is required for the precise determination of biases. Such a network solution is time consuming and difficult to achieve for very large regions such as Europe or China. Therefore, we developed a multi-layer processing scheme for precise point positioning (PPP) regional augmentation to avoid processing large networks. Furthermore, we use L1 and L2 raw observations and estimate atmospheric delays, which were properly constrained to the atmospheric corrections derived from the reference stations. Therefore, inaccurate representation of atmospheric delays due to temporal and/or spatial atmospheric fluctuations in the processing can be compensated. The proposed scheme of PPP regional augmentation was implemented into the operational real-time PPP service system at GFZ for validation. The real-time orbit and clock corrections, the uncalibrated phase delays, and regional augmentation corrections are generated by this system. The augmentation corrections from the regional network are investigated and the positioning performance in terms of positioning accuracy and time for fixed solution is demonstrated in real-time. Our results indicate that a reliable fixing is possible after 5 s on average. The positioning accuracy is about 12, 10, and 25 mm in east, north, and vertical direction, respectively. 相似文献
13.
This paper compares estimates of station coordinates from global GPS solutions obtained by applying different troposphere
models: the Global Mapping Function (GMF) and the Vienna Mapping Function 1 (VMF1) as well as a priori hydrostatic zenith
delays derived from the Global Pressure and Temperature (GPT) model and from the European Centre for Medium-Range Weather
Forecasts (ECMWF) numerical weather model data. The station height differences between terrestrial reference frames computed
with GMF/GPT and with VMF1/ECMWF are in general below 1 mm, and the horizontal differences are even smaller. The differences
of annual amplitudes in the station height can also reach up to 1 mm. Modeling hydrostatic zenith delays with mean (or slowly
varying empirical) pressure values instead of the true pressure values results in a partial compensation of atmospheric loading.
Therefore, station height time series based on the simple GPT model have a better repeatability than those based on more realistic
ECMWF troposphere a priori delays if atmospheric loading corrections are not included. On the other hand, a priori delays
from numerical weather models are essential to reveal the full atmospheric loading signal. 相似文献
14.
This study evaluates the quality of GPS radio occultation (RO) atmospheric excess phase data derived with single- and double-difference
processing algorithms. A spectral analysis of 1 s GPS clock estimates indicates that a sampling interval of 1 s is necessary
to adequately remove the GPS clock error with single-difference processing. One week (May 2–8, 2009) of COSMIC/FORMOSAT-3
data are analyzed in a post-processed mode with four different processing strategies: (1) double-differencing with 1 s GPS
ground data, (2) single-differencing with 30 s GPS clock estimates (standard COSMIC Data Analysis and Archival Center product),
(3) single-differencing with 5 s GPS clocks, and (4) single-differencing with 1 s GPS clocks. Analyses of a common set of
5,596 RO profiles show that the neutral atmospheric bending angles and refractivities derived from single-difference processing
with 1 s GPS clocks are the highest quality. The random noise of neutral atmospheric bending angles between 60 and 80 km heights
is about 1.50e−6 rad for the single-difference cases and 1.74e−6 rad for double-differencing. An analysis of pairs of collocated
soundings also shows that bending angles derived from single-differencing with 1 s GPS clocks are more consistent than with
the other processing strategies. Additionally, the standard deviation of the differences between RO and high-resolution European
Center for Medium range Weather Forecasting (ECMWF) refractivity profiles at 30 km height is 0.60% for single-differencing
with 1 and 5 s GPS clocks, 0.68% for single-differencing with 30 s clocks, and 0.66% for double-differencing. A GPS clock-sampling
interval of 1 s or less is required for single- and zero-difference processing to achieve the highest quality excess atmospheric
phase data for RO applications. 相似文献
15.
Estimating the motion of atmospheric water vapor using the Global Positioning System 总被引:1,自引:0,他引:1
Water vapor is both an important component in the atmosphere for the transport of energy and a noise source for space geodetic
observations of the Earth's surface, such as from GPS and interferometric SAR (InSAR) measurements. GPS data collected from
ground receivers are sensitive to the total amount of water vapor above the antenna and data from continuously operating GPS
receivers are routinely used to estimate delays caused by atmospheric water vapor. Using these time series of atmospheric
delay, we have estimated the motion of atmospheric water vapor above GPS networks. The motion above each site is determined
by comparing the time series from different sites and estimating relative time offsets in these time series. These are then
used to determine the velocity field of the atmospheric delays as they move across the network. We have compared the results
with similar estimates inferred from geostationary satellite data and found clear correlation on several occasions. Such results
can be useful for improving the understanding of the energy transport in the atmosphere, the spatial interpolation of water
vapor, and for calibrating InSAR observations for delays caused by water vapor.
Electronic Publication 相似文献
16.
Estimation and evaluation of real-time precipitable water vapor from GLONASS and GPS 总被引:1,自引:0,他引:1
Cuixian Lu Xingxing Li Maorong Ge Robert Heinkelmann Tobias Nilsson Benedikt Soja Galina Dick Harald Schuh 《GPS Solutions》2016,20(4):703-713
The revitalized Russian GLONASS system provides new potential for real-time retrieval of zenith tropospheric delays (ZTD) and precipitable water vapor (PWV) in order to support time-critical meteorological applications such as nowcasting or severe weather event monitoring. In this study, we develop a method of real-time ZTD/PWV retrieval based on GLONASS and/or GPS observations. The performance of ZTD and PWV derived from GLONASS data using real-time precise point positioning (PPP) technique is carefully investigated and evaluated. The potential of combining GLONASS and GPS data for ZTD/PWV retrieving is assessed as well. The GLONASS and GPS observations of about half a year for 80 globally distributed stations from the IGS (International GNSS Service) network are processed. The results show that the real-time GLONASS ZTD series agree quite well with the GPS ZTD series in general: the RMS of ZTD differences is about 8 mm (about 1.2 mm in PWV). Furthermore, for an inter-technique validation, the real-time ZTD estimated from GLONASS-only, GPS-only, and the GPS/GLONASS combined solutions are compared with those derived from very long baseline interferometry (VLBI) at colocated GNSS/VLBI stations. The comparison shows that GLONASS can contribute to real-time meteorological applications, with almost the same accuracy as GPS. More accurate and reliable water vapor values, about 1.5–2.3 mm in PWV, can be achieved when GLONASS observations are combined with the GPS ones in the real-time PPP data processing. The comparison with radiosonde data further confirms the performance of GLONASS-derived real-time PWV and the benefit of adding GLONASS to stand-alone GPS processing. 相似文献
17.
Pierre Bosser Olivier Bock Christian Thom Jacques Pelon Pascal Willis 《Journal of Geodesy》2010,84(4):251-265
This paper investigates the impact of rapid small-scale water vapor fluctuations on GPS height determination. Water vapor
measurements from a Raman lidar are used for documenting the water vapor heterogeneities and correcting GPS signal propagation
delays in clear sky conditions. We use data from four short observing sessions (6 h) during the VAPIC experiment (15 May–15
June 2004). The retrieval of wet delays from our Raman lidar is shown to agree well with radiosonde retrievals (bias and standard
deviation (SD) were smaller than 1 and 2.8 mm, respectively) and microwave radiometers (from two different instruments, bias
was 6.0/−6.6 mm and SD 1.3/3.8 mm). A standard GPS data analysis is shown to fail in accurately reproducing fast zenith wet
delay (ZWD) variations. The ZWD estimates could be improved when mean post-fit phase residuals were removed. Several methodologies
for integrating zenith lidar observations into the GPS data processing are also presented. The final method consists in using
lidar wet delays for correcting a priori the GPS phase observations and estimating a scale factor for the lidar wet delays
jointly with the GPS station position. The estimation of this scale factor allows correcting for a mis-calibration in the
lidar data and provides in the same way an estimate of the Raman lidar instrument constant. The agreement of this constant
with an independent determination using radiosonde data is at the level of 1–4%. The lidar wet delays were derived by ray-tracing
from zenith pointing measurements: further improvement in GPS positioning is expected from slant path lidar measurements that
would properly account for water vapor anisotropy. 相似文献
18.
Regional reference network augmented precise point positioning for instantaneous ambiguity resolution 总被引:28,自引:12,他引:16
Integer ambiguity fixing can significantly shorten the initialization time and improve the accuracy of precise point positioning
(PPP), but it still takes approximate 15 min of time to achieve reliable integer ambiguity solutions. In this contribution,
we present a new strategy to augment PPP estimation with a regional reference network, so that instantaneous ambiguity fixing
is achievable for users within the network coverage. In the proposed method, precise zero-differenced atmospheric delays are
derived from the PPP fixed solution of the reference stations, which are disseminated to, and interpolated at user stations
to correct for L1, L2 phase observations or their combinations. With the corrected observations, instantaneous ambiguity resolution
can be carried out within the user PPP software, thus achieving the position solutions equivalent to the network real-time
kinematic positioning (NRTK). The strategy is validated experimentally. The derived atmospheric delays and the interpolated
corrections are investigated. The ambiguity fixing performance and the resulted position accuracy are assessed. The validation
confirms that the new strategy can provide comparable service with NRTK. Therefore, with this new processing strategy, it
is possible to integrate PPP and NRTK into a seamless positioning service, which can provide an accuracy of about 10 cm anywhere,
and upgrade to a few centimeters within a regional network. 相似文献
19.
Qiang Chen Guoxiang Liu Xiaoli Ding Jyr-Ching Hu Linguo Yuan Ping Zhong M. Omura 《International Journal of Applied Earth Observation and Geoinformation》2010
A method for tightly integrating GPS observations and the persistent scatterer (PS) interferometric synthetic aperture radar (InSAR) is proposed to detect vertical ground motion in Hong Kong, China. The tropospheric zenith wet delays (ZWD) derived from GPS observations at sites in the SAR scenes are used first to model and correct for the tropospheric effects in the interferograms generated from the SAR images. The vertical motion rates (VMR) of the GPS sites determined based on the continuous GPS observations obtained at the sites are then used as constraints in the PS InSAR solutions to further enhance the quality of the solutions. Data from 12 continuous tracking GPS sites in Hong Kong and 8 ENVISAT ASAR images acquired during 2006–2007 are used to demonstrate the application of the proposed method. The results from the example show that the method is capable of detecting accurately the vertical ground motion. 相似文献
20.
成都地区地基GPS观测网遥感大气可降水量的初步试验 总被引:7,自引:0,他引:7
利用首个成都地区地基GPS观测网2004年7~9月30s间隔的测量数据,通过Bernese GPS SoftwareV4.2解算出30min间隔的天顶总延迟量,结合自动气象站获得的气象资料计算出30min间隔的GPS遥感的大气可降水量。与根据气象探空站探测资料算出的可降水量进行统计对比,确定出本次GPS遥感可降水量试验的精度为3.09mm,两种可降水量时间序列呈现高度的一致性。同时验证了计算对流层加权平均温度的Bevis经验公式在成都地区的适用性。 相似文献