The present study deals with the determination of Mount Olympus summit(Mytikas),exploiting modern observations such as Global Navigation Satellite Systems(GNSS)and existing geodetic information.The last official Olymp...The present study deals with the determination of Mount Olympus summit(Mytikas),exploiting modern observations such as Global Navigation Satellite Systems(GNSS)and existing geodetic information.The last official Olympus height determination goes back 102 years by the Swiss surveyor M.Kurz.Since then,only unofficial measurement campaigns have taken place.There is a variety of released heights,which range from 2917 to 2919 meters.In September and October of 2022,we conducted a GNSS campaign,focusing on the area of highest Olympus peaks.Employing precise GNSS measurements(accuracy of 1-3 cm),in conjunction with height information from Greece’s National Triangulation Network(5-10 cm accuracy)and an appropriate,recent geoid model(5-6 cm accuracy),we estimate through the so-called GNSS-levelling,the height of Olympus to 2917.727 m with respect to Greece’s officially accepted mean sea level and 2918.390 m with respect to the global vertical datum.Our estimation of Olympus highest peak shows remarkable consistency at the level of 12.8 cm to that of M.Kurz in 1921.展开更多
A method to determine the design value of the extreme wave height is introduced in this paper. The method is, based on the theoretical distribution of wave heights or the experiential probability distribution of wave ...A method to determine the design value of the extreme wave height is introduced in this paper. The method is, based on the theoretical distribution of wave heights or the experiential probability distribution of wave heights, to calculate the mode of the extreme wave height and the design value with good assuredness. In fitting the experiential distribution of the observed wave heights, the paper adopts the simulating function of F(x) = 1 - exp[ ?axb exp( -cxd )] and the non-linear parameter in the function is determined by the Non-Linear Least Square Method. The practical application of the method has proved that it is not only simple and convenient, but also very effective in engineering design practice.展开更多
A new temporal gravity field model called WHU-Grace01s solely recovered from Gravity Recovery and Climate Experiment （GRACE） K-Band Range Rate （KBRR） data based on dynamic integral approach is presented in this pa...A new temporal gravity field model called WHU-Grace01s solely recovered from Gravity Recovery and Climate Experiment （GRACE） K-Band Range Rate （KBRR） data based on dynamic integral approach is presented in this paper. After meticulously preprocessing of the GRACE KBRR data, the root mean square of its post residuals is about 0.2 micrometers per second, and seventy-two monthly temporal solutions truncated to degree and order 60 are computed for the period from January 2003 to December 2008. After applying the combi- nation filter in WHU-Grace01s, the global temporal signals show obvious periodical change rules in the large-scale fiver basins. In terms of the degree variance, our solution is smaller at high degrees, and shows a good consistency at the rest of degrees with the Release 05 models from Center for Space Research （CSR）, GeoForschungsZentrum Potsdam （GFZ） and Jet Pro- pulsion Laboratory 0PL）. Compared with other published models in terms of equivalent water height distribution, our solution is consistent with those published by CSR, GFZ, JPL, Delft institute of Earth Observation and Space system （DEOS）, Tongji University （Tongji）, Institute of Theoretical Geodesy （ITG）, Astronomical Institute in University of Bern （AIUB） and Groupe de Recherche de Geodesie Spatiale （GRGS}, which indicates that the accuracy of WHU-Grace01s has a good consistency with the previously published GRACE solutions.展开更多
An approach for determining cirrus height with multiple scattering effect using data from a Mie scattering lidar is proposed. We compute the exact extinction coefficients of cirrus via altitude. The regulated height o...An approach for determining cirrus height with multiple scattering effect using data from a Mie scattering lidar is proposed. We compute the exact extinction coefficients of cirrus via altitude. The regulated height of cirrus is obtained through multiple scattering factors. Experimental result demonstrates that the proposed approach can be used to determine effectively cirrus height with multiple scattering.展开更多
Fringe projection profilometry(FPP)is a method that determines height by analyzing distortional fringes,which is widely used in high-accuracy 3D imaging.Now,one major reason limiting imaging speed in FPP is the projec...Fringe projection profilometry(FPP)is a method that determines height by analyzing distortional fringes,which is widely used in high-accuracy 3D imaging.Now,one major reason limiting imaging speed in FPP is the projection device;the capture speed of high-speed cameras far exceeds the projection frequency.Among various devices,an LED array can exceed the speed of a high-speed camera.However,non-sinusoidal fringe patterns in the LED array systems can arise from several factors that will reduce the accuracy,such as the spacing between adjacent LEDs,the inconsistency in brightness across different LEDs,and the residual high-order harmonics in binary defocusing projection.It is challenging to resolve by other methods.In this paper,we propose a method that creates a look-up table using system calibration data of phase-height models.Then we utilize the look-up table to compensate for the phase error during the reconstructing process.The foundation of the proposed method relies on the time-invariance of systematic error;any factor that impacts the sinusoidal characteristic would present as an anomaly in the unwrapped phase.Experiments have demonstrated that the root mean square errors(RMSEs)of the results yielded by the proposed method were reduced by over 90%compared to those yielded by the traditional method,reaching 20μm accuracy.This paper offers an alternative approach for high-speed and high-accuracy 3D imaging with an LED array and presents a workable solution for addressing complex errors from non-sinusoidal fringes.展开更多
文摘The present study deals with the determination of Mount Olympus summit(Mytikas),exploiting modern observations such as Global Navigation Satellite Systems(GNSS)and existing geodetic information.The last official Olympus height determination goes back 102 years by the Swiss surveyor M.Kurz.Since then,only unofficial measurement campaigns have taken place.There is a variety of released heights,which range from 2917 to 2919 meters.In September and October of 2022,we conducted a GNSS campaign,focusing on the area of highest Olympus peaks.Employing precise GNSS measurements(accuracy of 1-3 cm),in conjunction with height information from Greece’s National Triangulation Network(5-10 cm accuracy)and an appropriate,recent geoid model(5-6 cm accuracy),we estimate through the so-called GNSS-levelling,the height of Olympus to 2917.727 m with respect to Greece’s officially accepted mean sea level and 2918.390 m with respect to the global vertical datum.Our estimation of Olympus highest peak shows remarkable consistency at the level of 12.8 cm to that of M.Kurz in 1921.
文摘A method to determine the design value of the extreme wave height is introduced in this paper. The method is, based on the theoretical distribution of wave heights or the experiential probability distribution of wave heights, to calculate the mode of the extreme wave height and the design value with good assuredness. In fitting the experiential distribution of the observed wave heights, the paper adopts the simulating function of F(x) = 1 - exp[ ?axb exp( -cxd )] and the non-linear parameter in the function is determined by the Non-Linear Least Square Method. The practical application of the method has proved that it is not only simple and convenient, but also very effective in engineering design practice.
基金supported by the National 973Program of China(2013CB733302)the National Natural Science Foundation of China(41131067,41174020,41374023,41474019)+2 种基金the Open Research Fund Program of the State Key Laboratory of Geodesy and Earth's Dynamics(SKLGED2015-1-3-E)the open fund of State Key Laboratory of Geographic Information Engineering(SKLGIE2013-M-1-3)the open fund of Key Laboratory of Geospace Environment and Geodesy,Ministry of Education(13-02-05)
文摘A new temporal gravity field model called WHU-Grace01s solely recovered from Gravity Recovery and Climate Experiment （GRACE） K-Band Range Rate （KBRR） data based on dynamic integral approach is presented in this paper. After meticulously preprocessing of the GRACE KBRR data, the root mean square of its post residuals is about 0.2 micrometers per second, and seventy-two monthly temporal solutions truncated to degree and order 60 are computed for the period from January 2003 to December 2008. After applying the combi- nation filter in WHU-Grace01s, the global temporal signals show obvious periodical change rules in the large-scale fiver basins. In terms of the degree variance, our solution is smaller at high degrees, and shows a good consistency at the rest of degrees with the Release 05 models from Center for Space Research （CSR）, GeoForschungsZentrum Potsdam （GFZ） and Jet Pro- pulsion Laboratory 0PL）. Compared with other published models in terms of equivalent water height distribution, our solution is consistent with those published by CSR, GFZ, JPL, Delft institute of Earth Observation and Space system （DEOS）, Tongji University （Tongji）, Institute of Theoretical Geodesy （ITG）, Astronomical Institute in University of Bern （AIUB） and Groupe de Recherche de Geodesie Spatiale （GRGS}, which indicates that the accuracy of WHU-Grace01s has a good consistency with the previously published GRACE solutions.
基金supported by the National Natural Science Foundation of China(No.41075013)the Central University Fund Project(Nos.ZXH2010D020 and ZXH2009B001)the National "973" Program of China(No.2010CB731800)
文摘An approach for determining cirrus height with multiple scattering effect using data from a Mie scattering lidar is proposed. We compute the exact extinction coefficients of cirrus via altitude. The regulated height of cirrus is obtained through multiple scattering factors. Experimental result demonstrates that the proposed approach can be used to determine effectively cirrus height with multiple scattering.
基金National Key Research and Development Program of China(2023YFB2806800)Open Research Projects of KLOMT(2022KLOMT02-02)。
文摘Fringe projection profilometry(FPP)is a method that determines height by analyzing distortional fringes,which is widely used in high-accuracy 3D imaging.Now,one major reason limiting imaging speed in FPP is the projection device;the capture speed of high-speed cameras far exceeds the projection frequency.Among various devices,an LED array can exceed the speed of a high-speed camera.However,non-sinusoidal fringe patterns in the LED array systems can arise from several factors that will reduce the accuracy,such as the spacing between adjacent LEDs,the inconsistency in brightness across different LEDs,and the residual high-order harmonics in binary defocusing projection.It is challenging to resolve by other methods.In this paper,we propose a method that creates a look-up table using system calibration data of phase-height models.Then we utilize the look-up table to compensate for the phase error during the reconstructing process.The foundation of the proposed method relies on the time-invariance of systematic error;any factor that impacts the sinusoidal characteristic would present as an anomaly in the unwrapped phase.Experiments have demonstrated that the root mean square errors(RMSEs)of the results yielded by the proposed method were reduced by over 90%compared to those yielded by the traditional method,reaching 20μm accuracy.This paper offers an alternative approach for high-speed and high-accuracy 3D imaging with an LED array and presents a workable solution for addressing complex errors from non-sinusoidal fringes.
