大地测量与地球动力学
 
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2013 Vol.33 Issue.3
Published 2013-06-18

1 STUDY ON 3-D VELOCITY STRUCTURE BY TEMPORARY DENSE 
SEISMOSTATIONS NETWORKS OF TANGSHAN EARTHQUEKE REGION
Lai Xiaoling,Sun Yi

Seismic tomography is used for processing the data of temporary seismostations networks in Tangshan region, and the velocity images of upper and mid crust in this earthquake region are obtained. The results show that, in the upper crust image, the velocity of two sides between the Tangshan fault zone are different,where the northwest side is high velocity zone  while the southeast side is low and the Tangshan fault is
belt with sharp velocity variety. Besides in the mid crust velocity image, it shows that there is low velocity belt
near EW strike in the centre of the studied area, and its location and strike are corresponding with the FengtaiYejituo fault which is near EW strike and in Tangshan epicenter region, along both of the depth and horizon, sharp velocity variety in crust exsits too.

2013 Vol. 33 (3): 1-4 [Abstract] ( 1147 ) PDF (1868 KB)   ( 2690 )
5 CRUSTAL MOTION ON SHANXI RIFT ZONE BEFORE AND AFTER WENCHUAN EARTHQUAKE
Liu Xia,Ma Jin,Zhan Wei,Zhang Fengshuang,Liang Fuxun, Fu Rongshan

Based on the newly obtained GPS data and the “block loading” FEA method, the crustal movement of Shanxi rift zone within two time span (1999—2007, 2007—2009) , which before and after the Wenchuan earthquake are simulated, respectively. The results show that the stress and strain fields assume opproximately unifrom NWSE extension before the earthquake. However, after the earthquake they are featured with remarkable compression accompanied with notable extension in the south region. Compared with 1999—2007, in 2007—2009 the maximum principal compressive and tensile stress increases 5-6 times and about 2 times,respectively, and from the north region to the south region of Shanxi rift zone, the direcion of the principal compressive stress changes from NW to NEE. Such stress and strain variation is verified by timeseries of acrossfault short level survey, long distance level survey and baseline of GPS continuous site. It indicates that the compressive and strikeslip displacement between Erdos block and North China Plain block increased after the Wenchuan earthquake. As a result, the crustal deformation and tectonic stress field of the Shanxi rift zone,which located in the boundary of the two blocks, change distinctly.

2013 Vol. 33 (3): 5-10 [Abstract] ( 1205 ) PDF (1373 KB)   ( 2668 )
11 PRESENT CRUSTAL DEFORMATION AND STRAIN CHARACTERISTICS OF DATONG BASIN
Qu Wei,Wang Qingliang,Zhang Qin,Peng Jianbing,Zhang Ming

Based on the high precision GPS monitoring data from 2006 to 2010 of China Crustal Movement Observation Network, the present crustal threedimensional velocity fields of Datong basin are obtained. Mainwhile by making use of strain analysis of graphical elements combined with significant test method, the present crustal strain parameters and its distribution features are also obtained, then the tectonic origin of ground fissures in Datong is analyzed. The results show that the present crustal movement of Datong basin demonstrates an overall horizontal extension and internal rift subsidence. The interior basin demonstrates overall tensile strain with the NW-SE direction, the most significant strain is at the northwest of the basin, with its value reaching 1.9×10-6/a, and this area is also the typical crack of Datong basin. The ground fissures in Datong basin is controlled by fault activities under the regional tensional stress field with the NW-SN direction.

2013 Vol. 33 (3): 11-15 [Abstract] ( 1152 ) PDF (754 KB)   ( 3483 )
16 RECENT HORIZONTAL CRUST DEFORMATION IN CENTRAL 
AND SOUTHERN QINGHAITIBET PLATEAU
Liu Zhiguang, Yang Bo, Lu Shuangyin, Feng Shengtao, Du Kaifu,Liang Hongbao

Based on the GPS regional station observations from 1999—2011 in the Tibet and Qinghai areas, using Euler model, multikernel function method and the spherical strain model, the regional NoNetRotation frame motion field and strains are calculated in the central and southern QinghaiTibet Plateau, and compares and analyses the results before and after the Wenchuan earthquake. The results show: The general movement features of the study area did not change greatly over the years. The crust motion is generally the EastWest tensive movement on the whole. In the central area, the crust motion is primarily the NorthSouth compressive movement, and disparts from south to north gradually. The north movement is mainly concentrated in the central Himalaya block and Lhasa block, and obviously weakened in the north Lhasa block. While in boundary of the Lhasa block and Qiangtang block, the motion changes obviously as the EastWest movement. The eastward motion is strengthened in the study area after the Wenchuan earthquake.

2013 Vol. 33 (3): 16-20 [Abstract] ( 1149 ) PDF (1223 KB)   ( 2834 )
21 CRUSTAL DEFORMATION CHARACTERISTICS IN FUJIAN REGION
Lin Shu, Wang Ziyan, Li Zuning,Guan Yumei,Chen Guang

The characteristics of crustal deformation and strain allocation in Fujian region are studied with continuous observation GPS data. The results of principal strain rate show that the direction of the principal extrusion deformation is NW in the coastal areas, and strain rate values is the largest in the southeast coastal area of Fujian,the strain rate values decreased gradually from the coastal areas to inland areas, at the same time, its direction deflected gradually. Meanwhile, deformation in two sides of the ZhengheHaifeng fault is obviously different. On its west side the direction of the principal extrusion deformation is NW, while on the east side of the southeast coastal areas ( south of 26 ° N ), the direction is NWEW, and in the northeast coastal area ( north of 26 ° N ), the direction is NWNS. On the other hand, there is a distinct shear deformation  near the  fault. The movement characteristics of some GPS stations in coastal area of Fjuian show that shear deformation is obvious in the region.

2013 Vol. 33 (3): 21-24 [Abstract] ( 1262 ) PDF (1173 KB)   ( 2591 )
25 COSEISMIC GRAVITY SIGNALS DETECTION FROM GRACE RESULTS BY EOF METHOD
Zhou Jiangcun, Sun Heping,Xu Jianqiao

The EOF method was used to extract coseismic gravity signals from GRACE monthly gravity field data. Because the GRACE satellites can't sensor the gravity changes due to vertical displacement of the Earth's surface, the gravity disturbance is used as the target signal. First, the temporal gravity disturbances at the grid points, with 0.5° resolution, on the Earth’s surface were calculated according to the GRACE monthly gravity field results, in which the 300 km fanfilter was used. And then the EOF method was applied to these temporal gravity disturbances to obtain the coseismic signals. The results show that the coseismic signals due to the recent 3 huge earthquakes, i.e. occurred in Sumatra, Chile and Japan, were successfully extracted, whereas the coseismic signals due to the Wenchuan earthquake, with relatively smaller magnitude, was not extracted because the signals are inundated by other signals and the error of GRACE data. In order to obtain the knowledge of how large an earthquake whose coseismic signal can be extracted from GRACE data should be, a simulation study was carried out by adding a known signal which was calculated in terms of the focal parameters of the Wenchuan earthquake according to dislocation theory, but with different magnitude. The simulation shows that the coseismic signal can be extracted when the magnitude reaches to Mw8.8 or larger; it is difficult to be extracted when the magnitude is smaller than
Mw8.6; and it is possible to be extracted when the magnitude is between Mw8.6 and Mw8.8.

2013 Vol. 33 (3): 25-29 [Abstract] ( 1180 ) PDF (1471 KB)   ( 2978 )
30 ANOMALY DETECTION ABOUT IONOSPHERIC ELECTRON DENSITY 
ON SUMATRA EARTHQUAKE IN APRIL 2012
Liu Ying, Dai Wujiao,Zhang Wenyi,Chen Biyan

Using the technology of ionospheric tomography, threedimensional ionospheric electronic density maps from April 1st to 15th in 2012 were reconstructed near the epicenter of Sumatra, The electron density anomaly detection is based on the doubled standard deviation. After excluding the solar activity and geomagnetic disturbance, the abnormal ionospheric electron density happened at the UT 10:00 on 11th, UT 6:00 on 13th, UT 6:0014:00 on 14th, UT 14:0016:00 on 15th, and they distributed mainly near the epicenter. The anomalies are likely a premise of the Sumatra earthquake in April.

2013 Vol. 33 (3): 30-33 [Abstract] ( 1151 ) PDF (2553 KB)   ( 2578 )
34 GLACIAL ISOSTATIC ADJUSTMENT MODELS CONSTRAINED BY 
JOINT INVERSION OF GPS AND GRACE SATELLITE OBSERVATIONS 
IN NORTH AMERICA
Zhao Shaorong, Liu Qingyuan,Zhu Jianjun

We present a joint inversion analysis of the GPSderived radial (vertical) deformation and GRACEderived gravity rates in North America to examine whether the icesheet models (ICE5G and ICE3G) can fit the satellite based observations. The results show that the existing icesheet models can not correctly predict the concentration of gravity change observed by GRACE in two areas of west and southeast of Hudson Bay. Tests of modifying ICE5G show that a reduction of ice thickness by about 20% in the west area of Hudson Bay and an increase by about 40% in the southeast are required to fit both observed vertical deformation and gravity changes by GPS and GRACE.The results of joint inversion demonstrate that the estimated effective lithosphere thickness (150 km, under a statistical confidence level of 80%) is apparently larger than that valuation (chouq 90 km) inferred from relative sealevel data, while the upperand lowermantle viscosity estimates (3.7 × 1020 Pa s; 1.9 × 1021 Pas; 90% confidence level) are about 20% smaller than those derived from sealevel indicators.

2013 Vol. 33 (3): 34-40 [Abstract] ( 1362 ) PDF (1633 KB)   ( 3303 )
41 ENVIRONMENT CORRECTION METHOD OF GROUNDBASED RADAR INTERFEROMETRY
Xu Yaming, Zhou Xiao, Wang Peng,Xing Cheng

The highfrequency signal was often used by groundbased radar as a communication signal, but it was susceptible to atmospheric effects. An environmental correction of radar signal was required to obtain the monitoring accuracy of better than millimeter in precision deformation monitoring using groundbased radar interferometry. A correction method based on the discrete stable point in the whole environment was proposed. The experiment proved that this method can optimize the measurement results for the smallscale scene.

2013 Vol. 33 (3): 41-43 [Abstract] ( 1084 ) PDF (746 KB)   ( 3007 )
44 COEFFICIENTS IN SERIES EXPANSION OF ASTRONOMICAL 
ATMOSPHERIC REFRACTION
Zhang Hanwei, Lei Weiwei,Ding Anmin

Using the theoretical relationship satisfied by atmospheric parameters between two points in the ray path, the influence of the atmosphere layer to astronomical atmospheric refraction was obtained. It not only considered the contribution of electronic displacement polarization of the dry air to astronomical atmospheric refraction, but also considered contribution of electronic displacement polarization and dipole steering polarization of water vapor. The integral representation is given, it does not depend on atmospheric distribution models, and it could adapte the calculation of different directions and meet the demand for highprecision.

2013 Vol. 33 (3): 44-47 [Abstract] ( 1060 ) PDF (455 KB)   ( 2446 )
48 GPS HEIGHT CONVERSION BASED ON SVM PARAMETER 
OPTIMIZATION METHOD
Li Mingfeng,Li Chunjin,Wang Yongming, Zhu Liqiang

On the basis of the theory of SVM, different parameter optimization methods of SVM modeling were discussed. Through three practical schemes of GPS height conversion, the characteristics and applied effects on SVM with the different parameter optimization methods were analyzed by the targets of optimization time and conversion accuracy.

2013 Vol. 33 (3): 48-51 [Abstract] ( 1202 ) PDF (629 KB)   ( 2784 )
52 RESEARCH ON TOTAL LEASTSQUARES METHODS FOR 
TRANSFORMATION OF GPS ELEVATION
Ding Haiyong,Sun Jingling

Curve surface fitting methods have been extensively utilized for the task of conversion GPS elevation to normal elevation. However, errors of the coordinates of GPS observations maybe propagate into the transformed normal elevation during  estimating the curve surface parameters. To analyze the influence of these errors in the observation data on the transformed elevation, we employed three models: the quadratic polynomial curve surface, cubic polynomial curve surface and moving quadratic curve surface, to study the accuracy of the converted normal elevation. LeastSquares  and two algorithms: Total LeastSquares and Weighted Total LeastSquares to estimate the parameters of these curve surfaces. The results from numerical experiments confirm that the accuracy of normal elevation have been considerably improved when errors of the coordinates of GPS observations data were modeled during the process of transformation.

2013 Vol. 33 (3): 52-55 [Abstract] ( 1336 ) PDF (445 KB)   ( 2728 )
56 EFFECT OF DIFFERENT AGING FACTORS ON DISPLACEMENT
Zhao Qing,Zhao Changsheng,Zhu Yu

The effect of aging factors on displacement was studied  on the basis of the survival regression model. Firstly, the numerical sequence of displacement data obtained by the original monitoring data were transformed to the “event status” sets {s(p)i|0, 1}. Secondly, the aging factors were divided into “months”, “quarters” and “years” , respectively. Finally, the “event status” sets are substituted into the survival regression model, and the effect on the displacement data was researched. The results show that the calculation results are slightly different with the different aging factors when calculating their effect on the displacement.

2013 Vol. 33 (3): 56-58 [Abstract] ( 1205 ) PDF (429 KB)   ( 2884 )
59 ESTIMATION OF GPS ZENITH TROPOSPHERIC DELAY BASED ON 
TERRAIN AND METEOROLOGICAL ELEMENTS
Liu Yanping, Zhang Lihui, Zhang Feilian

In order to solve the problem that the InSAR atmospheric correction is limited by the number of SAR image and weather conditions, a new tropospheric delay estimation method is proposed, which is based on the terrain and meteorological elements. The zenith tropospheric delay model is constructed and the zenith tropospheric delay is estimated by taking the GPS network in Beijing as an example. The result shows that the precision of the model is similar to the GPS tropospheric delay, which is amounted to mm, and can meet the requirements of InSAR atmospheric correction.

2013 Vol. 33 (3): 59-63 [Abstract] ( 1263 ) PDF (777 KB)   ( 2900 )
64 DETECTION OF EXCEPTIONAL CONJUGATE POINTS IN POINT 
CLOUD REGISTRATION
Chen Xijiang, Hua Xianghong, Lu Tieding,Wei Cheng,Zhang Yansuo

The block matrix is obtained by the detailed decomposition of vectormatrix that consists of exceptional conjugate points. The mathematical model of exceptional conjugate points detection is derived; the condition and minimum of exceptional points detection are given through the decomposed block matrix. The case study demonstrates that it is feasible to calculate the registration parameters after detecting and eliminating the exceptional conjugate points through this method, and it will be helpful to improve the accuracy of points cloud registration.

2013 Vol. 33 (3): 64-67 [Abstract] ( 1307 ) PDF (702 KB)   ( 3326 )
68 COMPARISON ON SLOPE CORRECTION METHODS FOR SATELLITE 
RADAR ALTIMETER DATA
Wang Haihong, Liu Yuchun, Wang Wenbo

To compare the performance of the three slope correction methods(the direct method, the indirect method and the relocation method), ERS1 data over the Vostok region in the Antarctic are processed based on the RAMP DEM model. The results show that the relocation method performs better than the other two methods. The accuracy of the direct method is the worst in the three methods.

2013 Vol. 33 (3): 68-71 [Abstract] ( 1304 ) PDF (629 KB)   ( 3290 )
72 ESTIMATION OF PRECIPITABLE WATER VAPOR BASED ON 
INTERPOLATED PRESSURE DATA
Liu Lilong,Yao Chaolong,Xiong Si, Huang Liangke

〗The meteorological data are obtained by pressure interpolation for the estimation of GPS precipitable water vapor (PWV) due to the lack of meteorological parameters at GPS sites. The pressure interpolation formula based on segmented height difference is derived by analyzing the relationship between the interpolated pressure at the GPS sites and the pressure at the nearby radiosonde (RS) stations, and the relationship between the interpolated pressure of the GPS sites and the height difference between the IGS stations and the nearby radiosonde stations using the standard atmosphere (SA) model. The new pressure interpolation formula has the same accuracy as the SA model, and the former is simple when the height difference is less than 100 m. GPS PWV is derived from the new pressure interpolation formula, Saastamoinen zenith hydrostatic delay (ZHD) model and the local weighted mean temperature of the atmosphere (Tm). By comparing with RS PWV, the results show that the new pressure interpolation model can be used to calculate GPS PWV with no meteorological data at GPS stations which the RMS error between GPS PWV obtained from the pressure interpolation formula based on segmented height difference and RS PWV is 13 mm.

2013 Vol. 33 (3): 72-78 [Abstract] ( 1302 ) PDF (1761 KB)   ( 4112 )
79 A FORECAST METHOD COMBINING x(1)(1)  WITH x(1)(n)  AS 
INITIAL VALUE OF GM(1,1) MODEL
Yuan Debao, Cui Ximin, Gao Ning

In order to reestablish the initial value for GM (1,1) model, we proposed a new approach to improve prediction accuracy of GM(1,1) model through optimization of the initial value, which is comprised of the first and the nth vector as the initialization, and derived from a method of least error summation of square. Then we discussed the parameter  which affects the fitting  results. By contrasting the improved one to the GM(1,1) about the simulation and prediction, we can conclude that the improved one is superior in prediction and simulation, and it is proved that the optimum one widen its suitable range.

2013 Vol. 33 (3): 79-82 [Abstract] ( 1141 ) PDF (777 KB)   ( 2648 )
83 POSITIONING ANALYSIS OF BEIDOU-2/COMPASS IN CHINA 
AND SURROUNDING SEAS
An Jiachun,Wang Zemin,Hu Zhigang, Xie Surui

Highperformance Beidou2/GPS receiver is used  to acquire Beidou2 and GPS data at the end of 2011. Then, the navigation and positioning features are analyzed under different movement modes, different regions and different satellite navigation systems. The results show that the separate Beidou2 navigation system can meet the demand of standard positioning in China and surrounding seas.

2013 Vol. 33 (3): 83-86 [Abstract] ( 1180 ) PDF (1101 KB)   ( 3805 )
87 LANDSLIDES MONITORING BASED ON INSAR TECHNIQUE
Wang Zhiyong,Zhang Jinzhi

According to the problems in the landslides monitoring using InSAR technique in practical applications, the research was carried out to monitor the landslides based on InSAR technique and multisource observations data. It monitored the landslides comprehensively using highresolution PALSAR data and multisource observations data on the basis of the method of radar interferometry. The landslides in Shijiaying which located in Fangshan region of Beijing were selected as the test area. Then it selected 7 PALSAR images during 2008 to 2010 to build 4 InSAR pairs. The monitoring precision can be achieved to 1 cm. The result proved that InSAR technique combined multisource observations data is a powerful and effective tool to measure surface deformation and  study landslides.

2013 Vol. 33 (3): 87-91 [Abstract] ( 1275 ) PDF (943 KB)   ( 3501 )
92 FUNDAMENTAL GEODATABASE DESIGN AND DLG DATA IMPORTING 
BASED ON FEATURE CODE
Liu Deer, Lan Xiaoji,Yuan Xiangui

According to the value of the classification and coding of geographic features in these aspects, such as organization of geographic information, data conversion, etc., a strategy was brought forward which could construct fundamental geographic database. In accordance with the principle of the present geographic feature classification, feature datasets were built in the major categories, and feature classes were built in the middle categories with geodatabase. On this basis, the mapping mechanism was established between feature classification code and feature class, and it was used to develop the DLG data software. Through the seamless integration between ArcGIS engine and ObjectArx, this software embedding in the process of AutoCAD was realized, and it can realize the warehousing of DLG data automatically and efficiently.

2013 Vol. 33 (3): 92-92-96 [Abstract] ( 1106 ) PDF (1251 KB)   ( 2937 )
97 RESEARCH ON APPLICATION OF TIGHTLY COUPLED INS/GNSS
〖JZ〗BASED ON ROBUST EXTENDED KALMAN FILTER
Miao Yuewang,Sun Fuping,Li Fei,Jing Xiaopeng

Tightly coupled INS/GNSS based on Robust Extended Kalman Filter algorithm is researched aiming at the observation outliers of GNSS in the INS/GNSS integrated navigation. Firstly, the INS error equations resolved into the Local Lever Frame as well as the INS/GNSS tightly coupled measurement equations are given. Secondly, the resolved model based on leastsquare algorithm is constructed according to the measurement equations and the equal weight covariance is constructed by the least square residual statistic, then calculation steps are given. Finally, measured data are processed to verify the algorithm. Results show that: when the outliers exist in GNSS observations, the tightly coupled INS/GNSS integration based on Robust Extended Kalman Filter can weaken the impact of the observation outliers effectively, and can improve the precision of integrated navigation system.

2013 Vol. 33 (3): 97-101 [Abstract] ( 1292 ) PDF (797 KB)   ( 3096 )
102 IMPROVING USER NAVIGATION PERFORMANCE WITHGLONASS IFDB
Pei Xiao,Chen Junping,Wang Jiexian

We analyze the correlation between GLONASS IFDB and receiver types and predict GLONASS IFDB based on derived model. By introducing GLONASS IFDB, several tests are performed using observations from several IGS stations. Results show that the navigation accuracy isremarkably improved by adding GLONASS IFDB.

2013 Vol. 33 (3): 102-105 [Abstract] ( 1183 ) PDF (501 KB)   ( 3271 )
106 INVERSION OF CRUSTAL STRAIN PARAMETERS BASED ON TOTAL LEAST SQUARES
Wang Leyang

The inversion of strain (rate) parameters based on total least squares (TLS) is studied, not only considering the error of observation(displacement or velocity field), but also considering the error effects of the coefficient matrix generally composed of monitoring points coordinates. All calculation formulae of crust strain (rate) parameters inversion based on total least squares (TLS) using monitoring points displacement or velocity field are deduced. Because there are constant part independent from monitoring points coordinates and coordinates part in the coefficient matrix, it is divided into two parts. The stochastic model of strain parameter inversion using coordinate displacement with TLS is solved by matrix vec operator. Through a simulated example, the comparisons and analysis of strain (rate) parameters are carried out between the total least squares (TLS) results and least squares (LS) results. The rationality and effectiveness of total least squares (TLS) in crust strain (rate) parameters inversion are confirmed.

2013 Vol. 33 (3): 106-110 [Abstract] ( 1215 ) PDF (374 KB)   ( 2224 )
111 EXTRACTION OF RIDGE LINES AND VALLEY LINES FROMMOUNTAINOUS LIDAR GROUND POINT CLOUD
Li Yun,Yang Bo,Yang Zhiqiang

A method of the extraction of ridge lines and valley lines from mountainous LIDAR ground point cloud is presented. We  extracted the normal vector and curvature of ground data based on differential geometry theory and local polynomial fitting,acquied the ridge points and valley points by computing extremum coefficient of curvature, generated ridge lines and valley lines based on the principle of minimum spanning tree. The results show that the method is feasible and effective.

2013 Vol. 33 (3): 111-115 [Abstract] ( 1230 ) PDF (1472 KB)   ( 3764 )
116 ON MODEL AND FORECAST OF DEFORMATION MONITORING DATA 
BASED ON SERIES AND PARALLEL COMBINATION PREDICTION
Gao Ning,Gao Caiyun

In order to improve the accuracy and reliability of forecasting deformation rnonitoring data, two kinds of combination prediction model structure, series combination(SC)and parallel combination(PC) are proposed.In the SC time series model, grey model and neural network to predict are separately used and then
 the predicting results are combined. In the PC the weight is used to combine different models, and the performance of the linear and nonlinear weight combination forecast are compared. Finally, a practical prediction case in building safety monitoring forecast used to explain the method. According to the experimental results, the proposed SC and PC combined method obviously can improve the prediction accuracy and therefore can be applied to deformation data analysis.

2013 Vol. 33 (3): 116-120 [Abstract] ( 1060 ) PDF (902 KB)   ( 2599 )
121 KEY TECHNOLOGY OF WEBGIS MONITORING SYSTEM BASED ONBEIDOU COMMANDER
Wang Wei,Dong Xurong,Zheng Kun

We take the combination of GPS and Beidou as the information transmission method to meet the accuracy in command and control applications in the special background. Meanwhile,we propose a method of command and control by network Beidou commander, so a serverside Beidou commander can command and monitor multiclient user machines remotely. The establishment of a “one to more” communication model increases the Beidou commander’s utilization. The system uses the combination of B / S and C / S as the WebGIS model which expanding the functions of the system and compatibility. Finally, on the basis of the above key technical the paper designs and completes a WebGIS monitoring system based on network Beidou commander, and the system has made a good application in practice.

2013 Vol. 33 (3): 121-124 [Abstract] ( 1162 ) PDF (503 KB)   ( 3055 )
125 ASSESSMENT OF GLOBAL IONOSPHERIC MAPS ANDINTERNATIONAL REFERENCE IONOSPHERE IN CHINA
Wang Cheng,Wang Jiexian

The  global ionospheric maps and international reference ionosphere as common ionosphere model are described. Observations in 2011 derived from three ionosondes in China are analysed. Comparative analysis between the measured data in China with global ionospheric maps and international reference ionosphere are represented in the work. The result indicates that global ionospheric maps is better than international reference ionosphere to describe the variation of electron content of ionosphere, and the accuracy of IRI2011 which is the latest version of international reference ionosphere is much higher than IRI2007.

2013 Vol. 33 (3): 125-128 [Abstract] ( 1239 ) PDF (2001 KB)   ( 3192 )
129 GNSS CYCLE SLIP DETECTION AND CORRECTION USING ROBUST 
POLYNOMIAL FITTING
Wang Fuli,Cheng Yingyan,Wei Cheng,Wang Xiaoming

The ability of polynomial fitting for detecting and correcting cycle slips is strongly affected by the errors of the carrier phase observations and the intervals of the observation data. The observation data being divided into several pieces will improve the results, however, the efficiency will be decreased.A method for combining epochdifferenced with robust estimation to improve the method of polynomial fitting is proposed. The numerical experiment is performed by using the real data of GPS /GLONASS. The results indicate that the method of robust polynomial fitting is more rigorous in theory and more powerful in practice for detecting and correcting cycle slips comparing with the normal polynomial fitting method.

2013 Vol. 33 (3): 129-132 [Abstract] ( 1252 ) PDF (1127 KB)   ( 2514 )
133 IONOSPHERE INTEGRITY MONITORING ANALYSIS OF CORS 
NETWORK IN HEBEI AREA
Zhao Chuanhua,Bei Jinzhong,Dang Yamin

In order to guarantee the reliability and availability of users’ positioning of Hebei CORS, ionosphere residual integrity monitoring indicator and ionosphere residual interpolation uncertainty indicator are used to conduct ionosphere integrity monitoring of the data of this network. The results show that the ionosphere delay calculated by these data within the decimeter level, and they are stable

2013 Vol. 33 (3): 133-135 [Abstract] ( 1251 ) PDF (713 KB)   ( 2766 )
136 ACCURACY ASSESSMENT OF COMBINED GPS/GALILEO 
SINGLE POINT POSITIONING
Luo Xiaomin,Cai Changsheng

A mathematic model of combined GPS/GALILEO single point positioning (SPP) is developed. On the basis of error corrections, the combined GPS/GALILEO SPP model is tested using the data of the MGEX tracking stations. The results indicate that the accuracy of the GPS/GALILEO SPP is not significantly improved when adding only one or two GALILEO satellites when the GPS observation satellites are sufficient. However, in the condition of insufficient number of GPS satellites, the accuracy of the combined GPS/GALILEO SPP is better than the GPSonly SPP.

2013 Vol. 33 (3): 136-140 [Abstract] ( 1116 ) PDF (1417 KB)   ( 3493 )
141 LOCAL -N-TH ORDER SURFACE FITTING AND CURVATURE 
ESTIMATION BASED ON SCATTERED-POINT CLOUD DATA
Yang Ronghua,Hua Xianghong,You Yangsheng

According to the poor precision of the triangular meshes geometry information extraction and the complicated local highorder surface fitting program of the scattered point cloud,  the local nth order surface fast fitting method and its curvature estimation formulas are deduced, which are on basis of the parametric local point cloud data, and the curvature calculation accuracy of the local quadric, cubic and fourth surface fitting has been compared by two practical examples. The comparison results verify that the theoretical formula is not only convenient to programming implementation, but also can ensure the calculation accuracy.

2013 Vol. 33 (3): 141-143 [Abstract] ( 1336 ) PDF (361 KB)   ( 3532 )
144 DEVELOPMENT OF THREE COMPONENTS PRESSURE METER 
BASED ON QUARTZ CRYSTAL RESONATOR
Cui Duxin, Wanng Qingliang, Tao Maosheng,Zhou Hui

A soil pressure meter based on the principle of forcefrequency linear relationship of ATcut quartz crystal resonator was introduced. The pressure meter consists of three perpendicular pressure sensors,a temperature sensor and an acquisition. The test results show that the sensor range is 0 ~ 1.0 MPa; the nonlinearity is less than 1.0%, the repeatability error is less than 0.05%; the dely error is less than 0.1%, and the temperature measurement accuracy is better than 0.01 ℃

2013 Vol. 33 (3): 144-147 [Abstract] ( 1134 ) PDF (726 KB)   ( 2731 )
148 UNCERTAINTY ANALYSIS OF IMAGE MEASUREMENT SYSTEM IN
HORIZONTAL REFERENCE DEVICE UPGRADING
Shi Yuhui,Lu Jie,Zheng Yong,Zhang Yi,Zhao Yifei

A highaccuracy horizontal reference device is very important for verification of instrument of surveying and metering. At present the debugging of highaccuracy horizontal reference device is menmade,which wastes much time and with large error,therefore,it is necessary to make this equipment automation retrofits.
The uncertainty analysis image measurement system after upgrading was studied by the combination of evaluation methods using standard of class A and class B,the results show that the transformation accuracy can meet the requirements of metrological verification.

2013 Vol. 33 (3): 148-150 [Abstract] ( 1033 ) PDF (334 KB)   ( 2666 )
151 A COMBINED METHOD OF FDA AND KFDA FOR MAGNETIC STORMS 
RECOGNITION
Kang Ruiqing,Liang Ying

To recognize the magnetic storms automatically from the horizontal component
of geomagnetism, a combined method of magnetic storms recognition based on Fisher and kernel Fisher discriminant analysis is presented. The data used in the study are derived from Ming tombs of Beijing geomagnetic station. In the case of the little number of the data samples, the average rate of this combined method for magnetic storms recognition is above 85%, and the recognition rate will be improved by the increasing amount of data samples.

2013 Vol. 33 (3): 151-154 [Abstract] ( 1121 ) PDF (681 KB)   ( 2740 )
155 DESIGN OF REMOTE REAL TIME MONITORING SYSTEM BASED
ON GPRS FOR RAILWAY ROADBED SUBSIDENCE
Feng Qian, Zhang Yi, Zhu Nian, Wang Hao

We have designed an automatic monitoring system for railway roadbed subsidence. The monitoring system is composed of sensor subsystem, data acquisition, transmission subsystem and data management subsystem. By means of remote realtime monitoring, it can monitor and issue the situations of subsidence of railway roadbed.

2013 Vol. 33 (3): 155-157 [Abstract] ( 1173 ) PDF (647 KB)   ( 2691 )
158 OFFSHORE GRAVITY MEASURMENTS OF CMONOC
Zhang Rui,Zou Rui,Han Yufei,Li Jianyong,Li Hui

Gravity measurements in Laos and Myanmar are reported.

2013 Vol. 33 (3): 158-159 [Abstract] ( 1064 ) PDF (449 KB)   ( 2551 )
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