09 December 2014, Volume 34 Issue 6
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jgg. 2014, 34(6): 1-8.
The research findings about regional stress state of Tanlu fault belt were summarized，including the maximum stress directions and magnitudes，the stability of regional faults and dynamic mechanism.The maximum stress direction is NEE in the north segment,and the southern segment,and nearly EW in the middle segment.The fault zone is mainly controlled by the Pacific Ocean plate and East Asia plate.The review shows the whole stress state of Tanlu fault zone，which provides basis for the future research on taking precautions against earthquake.
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jgg. 2014, 34(6): 9-13.
The leveling data crossing fault in Changjiazhuang，the NS component of tiltmeter in Yantai and gravity data in Taian before Laizhou M4.6 earthquake were analyzed.The result shows that each of the 3 kinds of observation data appeared midterm or shortterm trend abnormities.The characteristics of the abnormities is：the closer of the distance from epicenter，the earlier it occured，and the farther from epicenter，the longer it lasted for.The distance away epicenter of the farthest abnormal point reaches 276 km，and the abnormities are connected to the geological structure.
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jgg. 2014, 34(6): 14-19.
The data of 26 channel watertube tilter and extensometer at 6 permanent stations located around the epicenter of 2013 MinxianZhangxian earthquake with Ms 6.6 during the period of January 1，2009 and July 21，2013（one day before the MinxianZhangxian earthquake）were analyzed.The raw data were preprocessed and tidal analyzed，and the quality of the observation was estimated.The tidal response parameters and the smoothed day averaged value were obtained.The relationship between dynamic characteristics of the deformation rates and the earthquake were discussed.
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jgg. 2014, 34(6): 20-25. https://doi.org/P315.7
The coseismic displacement caused by Wenchuan earthquake（Ms8.0）was calculated with four seismic slip models using halfspace(Okada）and spherical dislocation theory（Shen et al)，respectively，and the displacement field calculated and the observation result were compared.Statistical significance caused by fault slipping and dislocation models were analyzed using the method of twofactor variance.Results show that coseismic displacements calculated by the spherical dislocation model is consistent with the observation results，the mean value of residual is 0.007 m，and its trace is 0.006 m.Near the fault rupture，both slipping factor and dislocation factor causing larger mean square deviation，the maximum is S2A=7.170 16 m2，S2B=91.407 7 m2，respectively.The significant influence of slipping distribution and dislocation model shows the characteristics of different space distribution，the former is embodied in the near field area，while dislocation model is mainly embodied in the farfield region.
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jgg. 2014, 34(6): 26-31.
Coseismic gravity change and deformation in layer viscoelastic medium caused by Yushu Ms7.1 were calculated using PSGRN/PSCMP based on different fault slip models.The results show that:1）Coseismic gravity change and displacement calculated for teleseimic waveform based on the fault slip model are more consistent with results from field survey；2）Coseismic gravity change only locates near by faults，and the range influenced by coseismic horizon displacements are obvious widely than that by coseimic gravity change；3）The obsolute gravity change during the period of two years before the earthquake and one month after the earthquake is obvious different from the result calculated，which indicats that observed obsolute gravity change implies earthquake preparation and coseismic change and postseismic change.
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jgg. 2014, 34(6): 32-36.
“Standard of Regional Gravity Survey” of China and “New Standard of the North American Gravity Correction” adopt both height correction and altitude correction.Li and Gotze derived an exact formula for computing the normal gravity values at any point in space.These three methods were compared by calculating the normal gravity values on the earth’s surface in China and its neighboring areas.The result indicates that the error calculated using the method adopted by “Standard of Regional Gravity Survey” of China is larger than the others，and the maximum error reaches 0.24×10-5 m/s2.The error is not a systematic one，it varies complexly，and closely relates to the terrain.
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jgg. 2014, 34(6): 37-40.
The relationship between precipitation，groundwater level and vertical component of GPS fixedobservation time series of images in Qiongzhong stations was systematically analyzed using groundwater and rainfall observation data of Jiaji well and Xiliu well during 1999 to 2012.The preliminary results show that rainfall，groundwater level and GPS vertical component all have a year cycle，and the relationship between each others is contravariant:when rainfall increases and groundwater level rises，the GPS vertical component decreases which means the land uplifts；otherwise，when the rainfall decreases and the groundwater level declines，GPS vertical component increases which means the land subsidences.Finally，the mechanism of the GPS vertical component changes caused by the rainfall and groundwater level variation were discused.
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jgg. 2014, 34(6): 41-43.
ICESat is the first satellite with laser altimeter.One of its purposes is to determinate the changes of Antarctic ice sheets.The repeat track analysis method was applied to calculate elevation changes of Antarctic ice sheets with ICESat GLA12 data from 2004 to 2008.The results show that the elevation changed evidently in West Antarctica，and decreased in many parts.However，the elevation changed does not obviously in the East Antarctic inland areas，decreases in parts of the East Antarctic coasts
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jgg. 2014, 34(6): 44-49.
Based on the nonlinear and nonstationary characteristics of total electric contents time series，the combination of SSA method and ARMA model was proposed to predict TEC.In the combination，ARMA model is used to predict the data which had been decomposed and filtered by SSA method，and the predicted value of each component is overlaid.The results calculated by the combination for 2010TEC data show that the mean relative precision of TEC prediction for 5 days is 92% by the combination，and the accuracy is improved of 4%，comparing with individual ARMA method.
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INCORPORATING SEASONAL VARIATIONS OF GLOBAL AND
REGIONAL TRF SOLUTIONS BASED ON GRACE MEASUREMENTSjgg. 2014, 34(6): 50-54.In this study，a seasonal loading model was imported into the ITRF2008 solutions based on GRACE（Gravity Recovery And Climate Environment）measurements to simulate hydrological loading，and comparison of the model to the original ITRF2008 for global reference frame realization was made.The seasonal components were simulated using either annual and semiannual terms or a nonparametric approach.Misfitting of the WRMS（Weighted Root Mean Squares）after 7parameter transformation calculated with the model decreases compared to that with the original ITRF2008 for more than 80% of daily GPS solutions.In general，the range of seasonal variations of daily solution at all sites is slightly larger in use of the seasonally augmented ITRF model.However，the results calculated with the model are more consistent with observed seasonal variations for 84% of the GPS sites.The findings mean that the use of the range of seasonal variations in the coordinate time series is decreased in use of ITRF2008 without seasonal terms relative to the true loading deformation，and that the results calculated with the TRF model included seasonal variations are more consistent with the observed GPS time series.
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jgg. 2014, 34(6): 55-59.
A carrierphase error model on the base of probability and statistics was proposed according to the differenced data of the dual frequency carrier phase.The results of examples calculated with the model show that calculation amount of determining the cycle slip is reduced greatly and the speed detection and repair of cycle slip is improved significantly.Moreover，data can be processed timely and the result is reliable.
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jgg. 2014, 34(6): 60-65.
A method based on the assumption of lithospheric local isostasy and CRUST1.0 model was deduced and a map of lithospheric thickness was made.The main lithospheric structure of China mainland and neighourhood was calculated with the method.Results of analyzing the main lithospheric structure by the aspects of the regional tectonic background and the mechanism of lithospheric thinning indicate that the lithospheric structure characteristics are not only associated with the geological age of blocks，but also maybe more are influenced by regional tectonic environment and mechanism of lithospheric thinning.
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jgg. 2014, 34(6): 66-71.
A practical mathematic model was established based on the least squares method and spherical harmonic analysis method for solving the EGM from disturbing potential data.The results show that there are some influences on the EGM results when the observation data are in different data quantity and sampling rate.The precisions of the EGMs recovered with different resolutions are different between each others.The result recovered with the spherical harmonic analysis method is better than that with the least squares method.
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jgg. 2014, 34(6): 72-75.
3 D temporalspatial variation regularity of ionospheric electron density were reconstructed by using the ionospheric tomography technique for the GNSS data of 126 stations on 10 June，2005.The diurnal variation regularity of ionospheric electron density distribution and variation characteristics of the ionospheric vertical structure in lowlatitude region were investigated and the prosess of occurrence，development and disappearance of the equatorial anomaly structure were carefully analyzed.The factors that impact the accuracy of ionospheric electron density were discussed，and some suggestions were given for further investigation of ionospheric tomography technique.
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jgg. 2014, 34(6): 76-80.
GNSS radio occultation technique has been proved to be an important method to investigate the ionospheric electron density in different levels.3D ray tracing is the best choice for analyzing the propagation of ray in ionosphere.A group of matrix equations from the differential equation in Cartesian coordinate was used to analyze the detail steps of ray tracing with the formulas.The NeQuick model is used to simulate the excess phase of L1，L2 and L5，and the simulated results are used to retrieval the electric density profile with absolute TEC inversion method with different band combination.The result of two numerical experiments shows that the combination L1-L5 is the preferable choice for vertical density profiles inversion under the identical observation conditions.
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jgg. 2014, 34(6): 81-85.
Performance of positioning with differential network of BDS/GPS fusion system was analyzed using pseudorange information through multiple reference stations differential positioning technology，based on BDS/GPS CORS test system.The experiment results indicate that positioning accuracy with multiple reference station BDS/GPS fusion system of single epoch realtime is not larger than 1 m，40 epoch realtime moving average positioning accuracy is about 0.5 m，pseudorange positioning accuracy is improved greatly.The method can meet demand of users for navigation and positioning.
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jgg. 2014, 34(6): 86-91.
The global ionospheric model for longterm prediction and shortterm prediction was analyzed through dividing the vertical total electron content（VTEC）into deterministic component and signal component，fitting the filtered signal of autocovariance function using 4order autoregressive model，and using the LeastSquares Collocation method.The results show that correlation coefficient between longterm prediction of trend component and global ionospheric model of CODE is 0.812，and the residuals between model fitted values for daily mean global total electron content（mean global TEC，MGTEC）and reference values are less than 4 TECu.The results of shortterm prediction show that the prediction precision is lower in the Southern Hemisphere than that in Northern Hemisphere，and the prediction precision is the lowest in the region between 20°N and 20°S of geomagnetic equator and in the ocean areas.Global prediction precision RMS is about 1-7 TECu，the average precision is about 2.4 TECu in Northern Hemisphere，and is
about 3.5 TECu in Southern Hemisphere. -
jgg. 2014, 34(6): 92-96.
A method based on the algorithm of coordinate transfer for precision evaluation of dynamic GNSS positioning was proposed.The method was validated with some examples.The results show that the precision with the algorithm of coordinate transfer is better than 1cm considering the influences of all kinds of errors.
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jgg. 2014, 34(6): 97-101.
For there is the problem of iterative calculation in robust extended Kalman filter（EKF），an algorithm of robust EKF based on the Vondrak gross error was proposed and applied to the GPS navigation and positioning.The first，it could identify and position the gross error of observations.Then，robust EKF model was used.In order to test the new model，dynamic GPS data was measured，double difference observation equation and velocity with acceleration kalman state equation of the model were built.The experiment results show that the new differential robust EKF model can resist the influence of gross errors in observation.Compared to the traditional robust EKF model，it can avoid resistance difference iteration in each epoch，and improve the efficiency of navigation solution.
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jgg. 2014, 34(6): 102-108.
Atmospheric delay is one of the main limiting factors for extracting groundsurface deformation with small rate over a large area with Interferometric Synthetic Aperture Radar（InSAR）technology.The delay consists of two components：the stratified component and the turbulent component.Stratified atmosphere delay can be plagued by both orbital error and deformation signal.It is difficult to separate this component by traditional interference methods.The residual error of stratified atmosphere delay sometimes could reach the range of deformation in some regions，which seriously impacts the accuracy of SAR interferometry measurement.A multiscale decomposition technique is proposed to evaluate stratified atmosphere delay，based on recognition of atmospheric components using North America NARR model.The results demonstrate that the method can effectively reduce the stratified components in InSAR interferometric phase.
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jgg. 2014, 34(6): 109-113.
The precision of gravity filed models established on GOCE data were compared and analysed according to geoid errors degree variances and degree variances of potential coefficient.The results indicate that：1）The precision of GOCEonly models is an order of magnitude higher than GRACEonly models，between 150 and 180 degree.2）The accuracy of gravity filed models which based on direct approach is highest，followed by timewise approach and the minimum is spacewise approach.3）At present，the maximum degree of earth gravity filed models which derived from GOCE datas is 250 and the accumulative geoid errors degree variances at 250 degree is about 14.7 cm.
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jgg. 2014, 34(6): 114-118.
The principle of velocity measurement using Beidou System(BDS）was introduced，the effects of each error correctionon on single point velocity measurement was analyzed and corresponding correction formulas were proposed.At last，the accuracy of BDS was evaluated according to the results of the experiments in which the results from dynamic velocity measurement and low dynamic velocity measurement were simulated using static data.The experiments show that the accuracy can reach cm/s in the simulation using Doppler Velocity Measurement Principle，and the accuracy can reach mm/s in the simulation using Doppler observation results derived by carrier phase.In low dynamic testing experiment，the mutual deviations between original Doppler velocity measurement results and integrated navigation equipment velocity measurement accord with cm/s level.While the mutual deviations between derived Doppler velocity measurement results and integrated navigation equipment velocity measurement accord with dm/s level.It can be concluded that the results from integrated navigation equipment are obviously affected by the motion of carriers.
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jgg. 2014, 34(6): 119-121.
The mean shift model for robust estimation and a new robust estimation model were proposed in the paper.In the use of the robust estimation model，it is unnecissary to change weight matrix for avoiding appearance of the rank deficient matrix.This method is suitable for processing of observation data.Examples show that the proposed method has good robustness.
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jgg. 2014, 34(6): 122-125.
The rigorous robust solution of lowaltitude sensor distortion parameters was proposed.Firstly，the initial parameters are obtained by 2D DLT，then the location of reference objects with gross or deviation is restrained by Huber algorithm.Finally，the rigorous solution of sensor distortion parameters is carried out by iterative computation with constrained condition.Experimental results show that the solution is reliable and practical，and the precision is higher than the bundle adjustment with unit weight or selecting weight iteration
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jgg. 2014, 34(6): 126-130.
A combination model based on the removerecovery principle was proposed.The model was established according to structure characteristics of each model，and analysis results of adaptability of the model under different terrain conditions of various engineering examples.The model is suitable to different terrain conditions.
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jgg. 2014, 34(6): 131-134.
Aimming at white noise，flicker noise，random walk and 1storder GaussMarkov process，the effect of inherent properties of the random sequence，including data length，sample rate，discontinuity of data and gross error，on the result of Allan Variance was analyzed in detail.The experimental results suggest that each property of random sequence affects the result of Allan variance in different degree.The author suggests a method for analyzing INS data.
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jgg. 2014, 34(6): 135-139.
The spectrum correction iterative algorithm and its correction algorithm are not a good solution to serious illposed problem，for the contradiction between convergent speed and illcondition reducing is difficult to deal with.At currently，the damping factor used by the improved algorithm still lacks an effective method to determinate.Aiming at this problem，the selfadaptive spectrum correction LU decomposition algorithm was proposed in the paper.The algorithm，which based on the spectrum correction equation，can avoid the matrix inverse problem by using the LU decomposition method for solving a normal equation.In the process of iteration，the damping factor is not fixed，and its value is adjusted adaptively according to the rate of residual decline.Examples show that，the algorithm can greatly reduce the iteration times to solve a normal equation with severely illconditioned matrix，and it also enhances the convergent speed and calculation accuracy greatly.
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jgg. 2014, 34(6): 140-143.
Robust adaptive filtering supposes that result of robust least square is accurate in current epoch.Through discrepancy between updated kinematic information and the measurements，navigation is adaptive.But in actual car navigation，rate of gross error is high，which makes accuracy of robust result drop.In order to solve this problem，this paper gives a robust adaptive filtering based on moving windows which regard mean error of robust least square solution of previous epochs as the threshold of current epoch.Experiments of road based on GPS/COMPASS realkinematic positioning indicate that this algorithm can improve accuracy of navigation in urban environment.
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jgg. 2014, 34(6): 144-147.
In order to reduce gyroscope random error，wavelet transform and higherorder AR models were used to process GNSS/INS data.The most of high frequency noise was eliminated by wavelet analysis，and higherorder AR model was used to describe the correlated noise.The results indicated that the method was effective for improving navigation accuracy during GPS outage.
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jgg. 2014, 34(6): 148-156.
For a harmonic function in outer space，ellipsoid lay outside the disturbance T(u,θ,λ) can be expressed by a series of harmonic functions ellipsoid，said to T(u,θ,λ) along the normal（n）direction derivation，only to the various series contains u factor derivation Qmn(u)，and contain the factors：u,θ,λ include remain Tmn(b,θ,λ) unchanged（including b for constant).T〖SX（〗T〖〗n〖SX）〗,the linear combination of，unobserved ground ellipsoid coordinate u,θ,λ，can be used to establish respectively the first second and third boundary value equation，end for boundary conditions that observation of the surface of the earth，then the other end the series and generative Taylor series of Δu，including Δu=u-b.Due to the boundary conditions and Δu are known，then the equation of the ellipsoid Tmn(b,θ,λ) can be solved ，and then the disturbance (uR,θ,λ) on the ground point or in outer space are calculated.As the ellipsoid is not used as the sphere，and ellipsoid function and the series solution are used，the results with the solution are closer to the actual the earth.Moreover，the method combining ground observation data（such as elevation）can avoid difficult of the changeable in use of a single layer’s inclination.
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jgg. 2014, 34(6): 157-161.A new landbased aircraft precision approach based on precise point positioning technology was proposed，which can support the blind landing of fixedwing aircraft，helicopters and unmanned aerial vehicles.The approach can reduce the risk of landing in bad weather and greatly simplifies the airport equipment and reduce the cost of construction of the airport.Moreover，a precise ephemeris compression method was presented in the paper，which can meet two hours of precise point positioning using two Beidou short messages.
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jgg. 2014, 34(6): 162-166.
Dam deformation is nonlinear，nonstationary and random which makes it difficult to accurately predict the deformation.Based on three kinds of single model，gray GM（1，1)，BP neural network and the common Carl filtering，the optimal nonnegative variable weight combination forecasting model was proposed.The model inherited the advantages of each single model.It is optimal for local prediction and accuracy is higher for the global prediction.The calculation results were compared with the optimal weighted combination model and each single one.The results show that the model prediction accuracy is higher；the root mean square error is 0.11 mm.And it can be applied to dam deformation prediction practically.
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jgg. 2014, 34(6): 167-172.
A method for analyzing tunnel deformation with the terrestrial laser scan（TLS）data based on the KNNSICP closing algorithm was proposed in the paper.First，the tunnel point cloud in the same area is extracted after registration.Second，the initial rotation and translation matrix are setted to unit and zero.The same slice of point cloud is closed by KNNSICP.At the last，the errors of corresponding points are calculated and the threshold is determined.The threshold is employed to extract the abnormal points before and after the deformation.The tunnel deformation would be determined by analyzing the changes of abnormal points.The results demonstrate the validity of the proposed method according to the example.
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jgg. 2014, 34(6): 173-176.
A in-situ calibration of CBT-type borehole-tiltmeter was designed for correctly understanding the drilling state.The remote calibration system takes RS-485 bus，as the basis and takes the stepper motor as the core.It is realized to calibrate remotely the sensors grid valued and linearity of the CBT-type borehole-tiltmeter.
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jgg. 2014, 34(6): 177-179.
A new type of micro displacement measurement sensor was introduced.The sensor can solve the shortcomings of the existing borehole strainmeters，and improve the reliability and the observation accuracy borehole strainmeter.
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jgg. 2014, 34(6): 180-182.
The purpose and the process of method validation of indoor verification of digital level were introduced.The measurement results，including eigenvalues precision，accuracy，uncertainty，were analyzed.The results of indoor and outdoor verification were compared.Statistical data indicate that the method is effective，and can be used as an alternative method for outdoor verification.
