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Izvestiya, Physics of the Solid Earth - The style of the seismotectonic deformation of the Earth’s crust in the Caucasus and its immediate surroundings corresponds to the thrust setting with... 相似文献
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基于四川GPS观测网络,本文提出采用低成本GPS-OEM板设计分米级差分GPS接收机。介绍四川GPS观测网络的工作原理,应用GPS观测网络改正由GPS轨道误差、电离层、对流层和大气折射引起的误差,将高精度的差分信息通过GPRS发给流动站来提高接收机的定位精度;论证了差分GPS的定位原理;最后提出整个系统的设计方案,用Thales DG14L OEM板处理GPS天线接收到的卫星信息,同时对GPRS天线接收数据中心差分信号进行差分运算。单片机控制软件采用汇编语言和C语言来编写。系统的实验结果表明,差分GPS接收机应用效果好,定位精度高,最重要的是降低了接收机的成本。 相似文献
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The global positioning system meteorology (GPS/MET) experiment was the first practical demonstration of global navigation satellite system (GNSS)-based active limb sounding employing the radio occultation technique. This method measures, as principal observable and with millimetric accuracy, the excess phase path (relative to propagation in vacuum) of GNSS-transmitted radio waves caused by refraction during passage through the Earth’s neutral atmosphere and ionosphere in limb geometry. It shows great potential utility for weather and climate system studies in providing an unique combination of global coverage, high vertical resolution and accuracy, long-term stability, and all-weather capability. We first describe our GPS/MET data processing scheme from excess phases via bending angles to the neutral atmospheric parameters refractivity, density, pressure and temperature. Special emphasis is given to ionospheric correction methodology and the inversion of bending angles to refractivities, where we introduce a matrix inversion technique (instead of the usual integral inversion). The matrix technique is shown to lead to identical results as integral inversion but is more directly extendable to inversion by optimal estimation. The quality of GPS/MET-derived profiles is analyzed with an error estimation analysis employing a Monte Carlo technique. We consider statistical errors together with systematic errors due to upper-boundary initialization of the retrieval by a priori bending angles. Perfect initialization and properly smoothed statistical errors allow for better than 1 K temperature retrieval accuracy up to the stratopause. No initialization and statistical errors yield better than 1 K accuracy up to 30 km but less than 3 K accuracy above 40 km. Given imperfect initialization, biases ≫ 2 K propagate down to below 30 km height in unfavorable realistic cases. Furthermore, results of a statistical validation of GPS/MET profiles through comparison with atmospheric analyses of the European Centre for Medium-range Weather Forecasts (ECMWF) are presented. The comparisons indicate the high utility of the occultation data in that very good agreement of upper troposphere/lower stratosphere temperature (better than 1.5 K rms, ≪ 0.5 K bias) is found for a region (Europe+USA) where the ECMWF analyses are known to be good, but poorer agreement for a region (Southern Pacific) where the analyses are known to be degraded. 相似文献
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Most GPS coordinate time series, surface displacements derived from the Gravity Recovery and Climate Experiment (GRACE), and loading models display significant annual signals at many regions. This paper compares the annual signals of the GPS position time series from the Crustal Dynamics Data Information System (CDDIS), estimates of loading from GRACE monthly gravity field models calculated by three processing centers (Center of Spatial Research, CSR; Jet Propulsion Laboratory, JPL; GeoForschungsZentrum, GFZ) and three geophysical fluids models (National Center for Environmental Prediction, NCEP; Estimating the Circulation and Climate of the Ocean, ECCO; Global Land Data Assimilation System, GLDAS) for 270 globally distributed stations for the period 2003-2011. The results show that annual variations derived from the level-2 products from the three GRACE product centers are very similar. The absolute difference in annual amplitude between any two centers is never larger than 1.25 mm in the vertical and 0.11 mm in horizontal displacement. The mean phase differences of the GRACE results are less than ten days for all three components. When we correct the GPS vertical coordinate time series using the GRACE annual amplitudes using the products from three GRACE analysis centers, we find that we are able to reduce the GPS annual signal in the vertical at about 80% stations and the average reduction is about 47%. In the north and the east, the annual amplitude is reduced on 77% and 72% of the stations with the average reduction 32% and 33%. We also compare the annual surface displacement signal derived from two environmental models; the two models use the same atmospheric and non-tidal ocean loading and differ only in the continental water storage model that we use, either NCEP or GLDAS. We find that the model containing the GLDAS continental water storage is able to better reduce the annual signal in the GPS coordinate time series. 相似文献
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GPS测量的广泛应用 总被引：1，自引：0，他引：1
GPS测量是测量界关心的重要课题之一 ,为此全国测量技术大会也曾以此为题召开过多次研讨会。由于测量仪器的不断开发、改进和完善 ,GPS在防灾、建设和气象等领域的应用正逐步扩展。目前 ,国土地理院正在备置电子基准点 ,实时动态测量便成为中心话题。下面介绍包括将来 GPS的可能性在内的有关多种GPS测量应用的见解。1 下世纪 GPS测量展望基本测量中的 GPS测量始于 1992年的 2次基准点测量 ,1995年引进了临时基准点测量。目前 ,国土地理院以 2 5 km间距的均等密度在整个日本列岛布设了约 10 0 0个 GPS连续观测点 (电子基准点 )。这… 相似文献
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Inversion of GPS meteorology data 总被引：14，自引：0，他引：14
K. Hocke 《Annales Geophysicae》1997,15(4):443-450
The GPS meteorology (GPS/MET) experiment, led by the Universities Corporation for Atmospheric Research (UCAR), consists of a GPS receiver aboard a low earth orbit (LEO) satellite which was launched on 3 April 1995. During a radio occultation the LEO satellite rises or sets relative to one of the 24 GPS satellites at the Earths horizon. Thereby the atmospheric layers are successively sounded by radio waves which propagate from the GPS satellite to the LEO satellite. From the observed phase path increases, which are due to refraction of the radio waves by the ionosphere and the neutral atmosphere, the atmospheric parameter refractivity, density, pressure and temperature are calculated with high accuracy and resolution (0.5–1.5 km). In the present study, practical aspects of the GPS/MET data analysis are discussed. The retrieval is based on the Abelian integral inversion of the atmospheric bending angle profile into the refractivity index profile. The problem of the upper boundary condition of the Abelian integral is described by examples. The statistical optimization approach which is applied to the data above 40 km and the use of topside bending angle profiles from model atmospheres stabilize the inversion. The retrieved temperature profiles are compared with corresponding profiles which have already been calculated by scientists of UCAR and Jet Propulsion Laboratory (JPL), using Abelian integral inversion too. The comparison shows that in some cases large differences occur (5 K and more). This is probably due to different treatment of the upper boundary condition, data runaways and noise. Several temperature profiles with wavelike structures at tropospheric and stratospheric heights are shown. While the periodic structures at upper stratospheric heights could be caused by residual errors of the ionospheric correction method, the periodic temperature fluctuations at heights below 30 km are most likely caused by atmospheric waves (vertically propagating large-scale gravity waves and equatorial waves).Present address: Communications Research Laboratory, Upper Atmosphere Section, 4-2-1 Nukui- Kita, Koganei- shi, Tokyo 184, Japan 相似文献
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利用GPS技术监测城市地面沉降,监测基准的合理选取对获得真实的形变结果至关重要.本文详细分析了城市沉降监测网基准的特点,针对传统基准模型的局限性提出了顾及板块运动、基准点稳定性以及其他系统误差影响的拟稳基准模型.该模型考虑了基准点自身的稳定性以及板块运动对高程形变的影响,同时采用系统参数统一各期基线框架以及区域拟稳基准,有效解决了因基准点不稳定性和基线框架不一致对形变结果造成的误差,确保正确形变信息的获取.最后通过六期西安市地面沉降监测网数据试验,验证了该方案的合理性和可靠性. 相似文献
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Relaxation of the coseismic stresses following an earthquake causes postseismic crustal deformation, which can last for days
to years. Continuous monitoring of postseismic deformation facilitates the understanding of the mechanism of deformation and
postseismic relaxation and viscous rheology. After the October 8, 2005 Kashmir earthquake, global positioning system data
for 8 months, starting from October, 2005 have been analyzed from three continuous sites located at Gulmarg, Amritsar, and
Jaipur. The average velocity during the observation period at Gulmarg (8.6 cm/year) is significantly higher than the Indian
plate velocity exhibiting postseismic crustal deformation. The velocity at Amritsar (5.9 cm/year) and Jaipur (5.1 cm/year)
is comparable to the Indian plate velocity. At Gulmarg, the logarithmic function fits well to the north–south component of
postseismic transients (~in the coseismic slip direction). The nature of decay in these transients suggests that the deformation
is mainly due to an afterslip, and the second possible contribution may be from the viscous relaxation process. This paper
presents the characteristics of postseismic transients and possible contributions from various postseismic mechanisms subsequent
to the Kashmir earthquake. 相似文献
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新疆帕米尔东北侧地区现今地壳运动的GPS监测研究 总被引：2，自引：0，他引：2
通过加密帕米尔东北侧地区的GPS监测网并进行复测,结合周边地区的IGS站数据,计算得到了该地区40多个GPS点位运动速率,由此得到了该地区的现今地壳形变速率图及GPS基准站的时间序列。结果表明：各GPS站主要运动方向为北北西,基本上与天山褶皱带走向正交,即形成对天山的正向挤压。伽师附近及其西南区的运动形态与周邻测站有所不同,表明伽师地区的构造变形与近几年地震活动有某种关联。环塔里木盆地周边点在各区内的速率变化较小,方向也基本一致,说明塔里木盆地内部变形较小或基本不变形。 相似文献
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GPS连续站水平位置坐标时间序列插值的一种新方法 总被引：1，自引：0，他引：1
GPS连续站多年的运行实践表明,其观测值在时间序列上并非时时连续,数据整体不完整率甚至已经达到了较高的比例。研究发现:在地壳形变的分析中,这样的结果直接影响着某种形变信息的正确提取。因此,插值已成为一项提高资料利用率、获取更多有效信息的必要途径。由于通常插值方法不注重空间上的联系,故对GPS的时间序列常难以给出恰如其分的插值结果。本文根据GPS连续观测资料各种信息的特征,提出了一种新的综合插值方法——"欧拉—周期—滤波—自噪"插值法。本文以天津GPS连续观测网为例,给出了实际操作方法,计算结果表明该插值法可以最大程度地保证各种信息不失真,较其它方法更为有效。 相似文献
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Using high precision GPS data for the period of 1999–2007 from the China Crustal Movement Observation Network, we have constructed a plate kinematic model of crustal deformation of Fenwei basin, China. We have examined different kinematic models that can fit the horizontal crustal deformation of the Fenwei basin using three steps of testing. The first step is to carry out unbiasedness and efficiency tests of various models. The second step is to conduct significance tests of strain parameters of the models. The third step is to examine whether strain parameters can fully represent the deformation characteristics of the 11 tectonic blocks over the Fenwei basin. Our results show that the degree of rigidity at the Ordos, Hetao, Yinshan and South China blocks is significant at the 95% confidence level, indicating the crustal deformation of these blocks can be represented by a rigid block model without the need to consider differential deformation within blocks. We have demonstrated that homogeneous strain condition is suitable for the Yinchuan basin but not for other 6 blocks. Therefore, inhomogeneous strains within blocks should be considered when establishing the crustal deformation model for these blocks. We have also tested that not all of the quadratic terms of strain parameters are needed for the Yuncheng-Linfen block. Therefore, four kinds of elastic kinematic models that can best represent the detailed deformation characteristics of the 11 blocks of Fenwei basin are finally obtained. Based on the established model, we have shown that the current tectonic strain feature of the Fenwei basin is mainly characterized by tensile strain in the NW–SE direction, and the boundaries betweem the Ganqing and Ordos blocks and the Shanxi graben possess the maximum shear strain. A comparison between our results and past geological and geophysical investigations further confirms that the model established in this paper is reasonable. 相似文献
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在电离层局部地区球对称假设下,推导了利用双频和单频无线电掩星观测数据,反演电离层电子密度剖面的两种方法. 双频反演的误差来自于载波相位的观测误差,单频反演误差则主要由伪距的观测精度决定. 由于载波相位测量精度比伪距测量精度高两个量级,因此双频反演的精度一般比单频反演的高些. 不过,两载波信号L1和L2之间的传播路径差异会给双频方法带来误差. 利用三维射线追踪的程序模拟的无线电掩星数据来评估这些方法,结果表明,反演出的电离层剖面与给定的模式电离层非常吻合,验证了两种方法的可靠性和准确性. 将这两种反演方法应用于处理实测的GPS/MET掩星观测数据,均能获取合理的电离层剖面信息. 且单频方法得到的反演剖面与双频方法相当一致, 这为利用LEO星载单频GPS接收机进行电离层掩星观测提供了理论基础. 相似文献
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We process the standard 30 s, static GPS data and the 1 s, high-rate GPS （HRGPS） data provided by the Crustal Movement Observation Network of China with GAMIT/GLOBK software package, and obtain the co- seismic displacements of near field and far field, and the epoch-by-epoch time series of HRGPS during Lushan earthquake. GPS data from about 20 sites in Sichuan province, which located between 40 and 450 km from the epicenter, are analyzed so as to study the characteristics of the static displacements and the dynamic crustal defor- mations, with periods ranging from several minutes to over a month. The result shows that： the static displacements caused by Lushan earthquake are limited to several centi- meters; the nearest station SCTQ at 43 km from the epi- center has the largest static displacement of about 2 cm, while the other stations generally have insignificant dis- placements of less than 5 mm. the stations in the east ofSichuan-Yunnan region shifts 5-10 mm toward the southwest, and the stations in the middle-west of Sichuan Basin moves indistinctively 1-2 mm toward the northwest; station SCTQ has the largest kinematic displacement of about 4 and 3 cm peak-to-peak on the north and east component, respectively, and is much greater than the static permanent displacement; for the stations located at a distance greater than 150 km from the epicenter, the kinematic motions are generally insignificant; exception- ally, station SCNC and station SCSN in central Sichuan Basin have significant kinematic motions although they are more than 200 km away from the epicenter. 相似文献
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基于GNSS(Global Navigation Satellite Systems)的发展,我们利用具有北斗、GLONASS和GPS三系统信号接收功能的接收机观测的数据,结合电离层总电子含量(Total Electron Content, TEC)的反演算法,提取出GNSS三系统观测的电离层TEC;同时,将GNSS三系统获取的TEC应用到电离层TEC地图、行进式扰动、不规则体结构和电离层的太阳耀斑响应等方面的研究中,这也是首次使用三种GNSS系统数据对电离层进行联合探测研究.研究结果表明,增加了北斗系统的GNSS三系统在研究中国地区电离层TEC地图、周日变化、逐日变化,行进式扰动以及电离层的实时监测等方面较单系统的GPS具有明显的优势. 相似文献
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Co-seismic deformation derived from GPS observations during April 20th, 2013 Lushan Earthquake,Sichuan, China 总被引：1，自引：1，他引：0
We process the standard 30 s, static GPS data and the 1 s, high-rate GPS (HRGPS) data provided by the Crustal Movement Observation Network of China with GAMIT/GLOBK software package, and obtain the co-seismic displacements of near field and far field, and the epoch-by-epoch time series of HRGPS during Lushan earthquake. GPS data from about 20 sites in Sichuan province, which located between 40 and 450 km from the epicenter, are analyzed so as to study the characteristics of the static displacements and the dynamic crustal deformations, with periods ranging from several minutes to over a month. The result shows that: the static displacements caused by Lushan earthquake are limited to several centimeters; the nearest station SCTQ at 43 km from the epicenter has the largest static displacement of about 2 cm, while the other stations generally have insignificant displacements of less than 5 mm. the stations in the east of Sichuan–Yunnan region shifts 5–10 mm toward the southwest, and the stations in the middle-west of Sichuan Basin moves indistinctively 1–2 mm toward the northwest; station SCTQ has the largest kinematic displacement of about 4 and 3 cm peak-to-peak on the north and east component, respectively, and is much greater than the static permanent displacement; for the stations located at a distance greater than 150 km from the epicenter, the kinematic motions are generally insignificant; exceptionally, station SCNC and station SCSN in central Sichuan Basin have significant kinematic motions although they are more than 200 km away from the epicenter. 相似文献