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An improved particle filter indoor fusion positioning approach based on Wi-Fi/PDR/geomagnetic field

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Defence Technology（防务技术） 2024年第2期32卷 443-458页

作者： Tianfa Wang Litao Han Qiaoli Kong Zeyu Li Changsong Li Jingwei Han Qi Bai Yanfei Chen college of geodesy and {2. Shandong University of Science and TechnologyQingdao266590China Key Laboratory of geomatics and Digital Technology of Shandong Province Shandong University of Science and TechnologyQingdao266590China

The existing indoor fusion positioning methods based on Pedestrian Dead Reckoning(PDR)and geomagnetic technology have the problems of large initial position error,low sensor accuracy,and geomagnetic *** this study,a novel indoor fusion positioning approach based on the improved particle filter algorithm by geomagnetic iterative matching is proposed,where Wi-Fi,PDR,and geomagnetic signals are integrated to improve indoor positioning *** important contribution is that geomagnetic iterative matching is firstly proposed based on the particle filter *** the positioning process,an iterative window and a constraint window are introduced to limit the particle generation range and the geomagnetic matching range *** position is corrected several times based on geomagnetic iterative matching in the location correction stage when the pedestrian movement is detected,which made up for the shortage of only one time of geomagnetic correction in the existing particle filter *** addition,this study also proposes a real-time step detection algorithm based on multi-threshold constraints to judge whether pedestrians are moving,which satisfies the real-time requirement of our fusion positioning *** experimental verification,the average positioning accuracy of the proposed approach reaches 1.59 m,which improves 33.2.compared with the existing particle filter fusion positioning algorithms.

关键词： Fusion positioning Particle filter Geomagnetic iterative matching Iterative window Constraint window

Determination of global geodetic parameters using satellite laser ranging to Galileo,GLONASS,and BeiDou satellites

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Satellite Navigation 2024年第1期5卷 240-257页

作者： Xingxing Li Jiaqing Lou Yongqiang Yuan Jiaqi Wu Keke Zhang School of geodesy and geomatics Wuhan University129 Luoyu RoadWuhan430079HubeiChina

The new Global Navigation Satellite System(GNSS)satellites,including GLONASS,Galileo,and BeiDou system,are equipped with Laser Retroreflector Arrays(LRA)to support Satellite Laser Ranging(SLR)tracking,which contributes to the estimation of global geodetic *** this study,we estimate the global geodetic parameters using the SLR observations to GNSS satellites and also investigate the effects of different data processing strategies on the estimated Earth Rotation Parameters(ERP),geocenter motion,and terrestrial *** results indicate that setting range bias parameters for each satellite-station pair can effectively account for the satellite-specific biases induced by LRAs,leading to smaller Root Mean Square Errors(RMSE)of the post-fit SLR ***,estimating the range biases for each satellite-station pair improves the accuracy of the estimated station coordinates and *** also examine the impact of different arc lengths on the estimates of ERP,geocenter motion,and terrestrial *** results show that extending arc length can significantly reduce the formal error of *** 7-day strategy produces the smallest RMSEs of 473 microarcseconds and 495 microarcseconds for the estimated X-and Y-component of pole coordinates,and 52.microseconds for length-of-day,***,the estimated geocenter motion is less affected by the arc length,even the shortest 1-day arc strategy can capture the seasonal variations of geocenter motion in Z *** scale estimation,extending the arc length notably improves the accuracy of the estimated station coordinates and scale,but this advantage becomes less noticeable in longer *** 7-day solution also obtains the closet scale results compared to ITRF2.14,with the RMSE of 2.10×10^(–9).

关键词： Satellite laser ranging GNSS Geodetic parameters Earth rotation parameters Geocenter motion Terrestrial scale

An improved algorithm based on equivalent sound velocity profile method at large incident angle

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Acta Oceanologica Sinica 2024年第2期43卷 161-167页

作者： Qianqian Li Qian Tong Fanlin Yang Qi Li Zhihao Juan Yu Luo college of geodesy and {2. Shandong University of Science and TechnologyQingdao 266590China college of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001China

With the development of ultra-wide coverage technology,multibeam echo-sounder(MBES)system has put forward higher requirements for localization accuracy and computational efficiency of ray tracing *** classical equivalent sound speed profile(ESSP)method replaces the measured sound velocity profile(SVP)with a simple constant gradient SVP,reducing the computational workload of beam ***,in deep-sea environment,the depth measurement error of this method rapidly increases from the central beam to the edge *** analyzing the positioning error of the ESSP method at edge beam,it is discovered that the positioning error increases monotonically with the incident angle,and the relationship between them could be expressed by polynomial ***,an error correction algorithm based on polynomial fitting is *** simulation experiment conducted on an inclined seafloor shows that the proposed algorithm exhibits comparable efficiency to the original ESSP method,while significantly improving bathymetry accuracy by nearly eight times in the edge beam.

关键词： equivalent sound speed profile ray tracing method large incident angle edge beam deep sea error correction multibeam echo-sounder system

Constraint on the focal mechanism of the 2.11 Tohoku earthquake from the radial modes

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geodesy and Geodynamics 2024年第1期15卷 27-32页

作者： Weikun Chen Hao Ding School of geodesy and geomatics Hubei LuoJia LaboratoryWuhan UniversityWuhan 430079China

Different from other normal modes of the Earth’s free oscillation that depend on all the six components(M_(rr),M_(tt),M_(pp),M_(rt),M_(rp),and M_(tp))of the centroid moment tensor,the amplitudes of the radial modes depend on the M_(rr)component(e.g.,scalar moment(M_(0)),dip(δ),and slip(λ))and hypocenter depth of the focal mechanism,and hence can be easily used to constrain these parameters of the focal *** this study,we use the superconducting gravimeter(SG)records after the 2.11 Tohoku earthquake to analyze the radial modes_(0)S_(0)and_(1)S_(0).Based on the solutions of the focal mechanism provided by the GCMT and USGS,we can obtain the theoretical amplitudes of these two radial *** the theoretical amplitudes with the observation amplitudes,it is found that there are obvious differences between the former and the latter,which means that the GCMT and USGS focal mechanisms cannot well represent the real focal mechanism of the 2.11 *** the GCMT solution as a reference and changing the depth and the three parameters of the M_(rr)moment,the scalar moment(M_(0))and the dip(δ)have significant influences,but the effects of the slip(λ)and the depth are *** comparisons,we provide a new constraint(M_(0)=5.8±0.09×10^(2.)N·m,δ=10.1±0.08°,λ=88°,and depth=2. km)for the focal mechanism of the 2.11 *** addition,we further determine the center frequency(1.631567±2.6e^(-6)mHz)and quality factor(2.46.4±50.1)of the_(1)S_(0)mode.

关键词： Focal mechanism Radial modes Gravity observation

An improved positioning model of deep-seafloor datum point at large incidence angle

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Journal of Oceanology and Limnology 2024年第1期42卷 90-100页

作者： Qianqian LI Shoulian CAO Fanlin YANG Yu LUO Qian TONG college of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150000China college of geodesy and {2. Shandong University of Science and TechnologyQingdao 266590China Key Laboratory of Ocean geomatics Ministry of Natural ResourcesQingdao 266590China

The inhomogeneous sound speed in seawater causes refraction of sound waves,and the elimination of the refraction effect is essential to the accuracy of underwater acoustic *** raytracing method is an indispensable tool for effectively handling ***,this method has a conflict between localization accuracy and computational *** equivalent sound speed profile(ESSP)method uses a simple sound speed profile(SSP)instead of the actual complex SSP,which can improve positioning precision but with residual *** residual error is especially non-negligible in deep water and at large beam incidence *** analyzing the residual error of the ESSP method through a simulation,an empirical formula of error is *** data collected in the sailing circle mode(large incidence angle)of the South China Sea are used for *** experiments show that compared to the ESSP method,the improved algorithm has higher positioning precision and is more efficient than the ray-tracing method.

关键词： underwater acoustic positioning seafloor datum points large incident angle equivalent sound speed profile(ESSP) deep water

Efficient 2.D MUSIC algorithm for super-resolution moving target tracking based on an FMCW radar

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geodesy and Geodynamics 2024年第5期15卷 504-515页

作者： Xuchong Yi Shuangxi Zhang Yuxuan Zhou School of geodesy and geomatics Wuhan UniversityWuhan 430079China Key Laboratory of Geospace Environment and geodesy Ministry of EducationWuhan 430079China

Frequency modulated continuous wave(FMCW)radar is an advantageous sensor scheme for target estimation and environmental ***,existing algorithms based on discrete Fourier transform(DFT),multiple signal classification(MUSIC)and compressed sensing,etc.,cannot achieve both low complexity and high resolution *** paper proposes an efficient 2.D MUSIC algorithm for super-resolution target estimation/tracking based on FMCW ***,we enhance the efficiency of 2.D MUSIC azimuth-range spectrum estimation by incorporating 2.D DFT and multi-level resolution searching ***,we apply the gradient descent method to tightly integrate the spatial continuity of object motion into spectrum estimation when processing multi-epoch radar data,which improves the efficiency of continuous target *** two approaches have improved the algorithm efficiency by nearly 2.4 orders of magnitude without losing accuracy and *** experiments are conducted to validate the effectiveness of the algorithm in both single-epoch estimation and multi-epoch tracking scenarios.

关键词： 2.-MUSIC FMCW radar Moving target tracking Super-resolution Algorithm optimization

A Web-Based Approach for the Efficient Management of Massive Multi-source 3D Models

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Journal of geodesy and Geoinformation Science 2024年第3期7卷 24-41页

作者： ZHAO Qiansheng TANG Ruibing PENG Mingjun GUO Mingwu School of geodesy and geomatics Wuhan UniversityWuhan 430079China Wuhan geomatics Institute Wuhan 430022China

Effectively managing extensive,multi-source,and multi-level real-scene 3D models for responsive retrieval scheduling and rapid visualization in the Web environment is a significant challenge in the current development of real-scene 3D applications in *** this paper,we address this challenge by reorganizing spatial and temporal information into a 3D geospatial *** introduces the Global 3D Geocoding System(G_(3)DGS),leveraging neighborhood similarity and uniqueness for efficient storage,retrieval,updating,and scheduling of these models.A combination of G_(3)DGS and non-relational databases is implemented,enhancing data storage scalability and ***,a model detail management scheduling strategy(TLOD)based on G_(3)DGS and an importance factor T is *** with mainstream commercial and open-source platforms,this method significantly enhances the loadable capacity of massive multi-source real-scene 3D models in the Web environment by 33%,improves browsing efficiency by 48%,and accelerates invocation speed by 40%.

关键词： massive multi-source real-scene 3D model non-relational database global 3D geocoding system importance factor massive model management

Suitable region of dynamic optimal interpolation for efficiently altimetry sea surface height mapping

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geodesy and Geodynamics 2024年第2期15卷 142-149页

作者： Jiasheng Shi Taoyong Jin School of geodesy and geomatics Hubei Luojia LaboratoryWuhan UniversityWuhan 430079China MOE Key Laboratory of Geospace Environment and geodesy Wuhan UniversityWuhan 430079China

The dynamic optimal interpolation(DOI)method is a technique based on quasi-geostrophic dynamics for merging multi-satellite altimeter along-track observations to generate gridded absolute dynamic topography(ADT).Compared with the linear optimal interpolation(LOI)method,the DOI method can improve the accuracy of gridded ADT locally but with low computational ***,considering both computational efficiency and accuracy,the DOI method is more suitable to be used only for regional *** this study,we propose to evaluate the suitable region for applying the DOI method based on the correlation between the absolute value of the Jacobian operator of the geostrophic stream function and the improvement achieved by the DOI *** verifying the LOI and DOI methods,the suitable region was investigated in three typical areas:the Gulf Stream(2.°N-50°N,55°W-80°W),the Japanese Kuroshio(2.°N-45°N,135°E-155°E),and the South China Sea(5°N-2.°N,100°E-12.°E).We propose to use the DOI method only in regions outside the equatorial region and where the absolute value of the Jacobian operator of the geostrophic stream function is higher than1×10^(-11).

关键词： Dynamic optimal interpolation Linearoptimal interpolation Satellite altimetry Sea surface height Suitable region

Numerical simulations of earthquake rupture induced by pressure perturbation

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geodesy and Geodynamics 2024年第5期15卷 477-487页

作者： Bingquan Ren Caijun Xu Guoyan Jiang Lei Yang School of geodesy and geomatics Wuhan UniversityWuhan 430079China Key Laboratory of Geospace Environment and geodesy Ministry of EducationWuhan UniversityWuhan 430079China Key Laboratory of Geophysical geodesy Ministry of Natural ResourcesWuhan 430079China

The subsurface fluid injection can cause pressure increase within faults,leading to earthquake ***,the factors controlling earthquake rupture due to pressure perturbation remain poorly *** resolve this problem,we simulate the physical processes of earthquake nucleation and rupture on strike-slip faults perturbated by pressure migration based on the slip-weakening *** kinds of factors,including background stress,fluid injection rates,the area of the pressurized region,fault geometry,and fault friction coefficients,are considered in our *** simulation results reveal that the ratio of shear stress to normal stress rather than their absolute values controls the rupture *** the large stress ratios,high injection rates,and large pressurized areas,earthquakes are prone to propagate as runaway ***,faults with large aspect ratios of length to width are also favorable for causing runaway *** contrast,the factors of fault strike,dip angles and friction coefficients have minor influence on rupture behavior.

关键词： Induced seismicity Finite element simulation Rupture mode