The estimation of glacier flow velocity on a short-term scale is very important for further glacier dynamics research.In this study,10 Sentinel-1 ascending images and 10 Sentinel-1 descending images of Urumqi Glacier ...The estimation of glacier flow velocity on a short-term scale is very important for further glacier dynamics research.In this study,10 Sentinel-1 ascending images and 10 Sentinel-1 descending images of Urumqi Glacier No.1 in 2017 were used to calculate the glacier flow velocity in a high coherence period by DIn SAR technology and MAI technology,while the offset tracking technology was used to estimate the glacier flow velocity in a low coherence period.Then,the monthly three-dimensional flow velocity of the glacier was calculated by the Helmert variance component estimation method.Finally,the accuracy of the estimated glacier flow velocity on a monthly scale was evaluated.The results showed that:(1)the monthly scale motion velocity of Urumqi Glacier No.1 in May,June,July,and August 2017 was 0.273 m/month,0.657 m/month,0.582 m/month,and 0.392 m/month,respectively.(2)The accuracy of glacier surface velocity from May 2017 to August 2017 was 0.033 m/month,0.026 m/month,0.034 m/month and 0.037 m/month,respectively.(3)The accuracy of glacier surface flow velocity from May 2017 to August 2017 was 0.018 m/month,0.031 m/month,0.029 m/month and 0.030 m/month,respectively.Therefore,the research methodology based on the Sentinel-1 ascending and descending data and presented in this paper was applicable to the estimation of monthly-scale flow velocity of mountain glaciers.展开更多
Navigation technology,which integrates vision,Inertial Measurement Unit(IMU),and Ultra-Wideband(UWB)sensors in GNSS-denied environments has gained a significant attention.However,inaccurate estimation of UWB anchor po...Navigation technology,which integrates vision,Inertial Measurement Unit(IMU),and Ultra-Wideband(UWB)sensors in GNSS-denied environments has gained a significant attention.However,inaccurate estimation of UWB anchor positions and improper sensor weighting among heterogeneous sensors significantly impairs the positioning accuracy and robustness of Visual-Inertial-UWB(VIU)systems.To accurately and rapidly estimate the UWB anchor positions,we employed the robust ridge nonlinear least-squares method to improve the accuracy and reliability of the estimated UWB anchor position.Additionally,we proposed a simple and effective method to assess the accuracy of the UWB anchor position using the geometric dilution precision principle,which facilitates rapid and accurate estimation of the UWB anchor position.Furthermore,we designed a method to calculate the estimated UWB anchor position error in real-world settings.Finally,we proposed a nonlinear optimization method with dynamically adaptive weighting based on the HELMERT variance component estimation principle,which assigns appropriate weights to heterogeneous sensors.To validate the feasibility and effectiveness of the proposed method,comprehensive simulations and real-world experiments were conducted.First,using Monte Carlo simulation and real-world experiments,we validated the effectiveness of the proposed methods for UWB anchor position and its accuracy estimation.Then,we conducted ablation experiments utilizing the open-source VIRAL and real-world datasets.The experimental results demonstrate that the proposed method exhibits superior positioning accuracy and robustness in contrast to the open-source VINS-MONO and VIR-SLAM methods.展开更多
基金funded by the Basic scientific research fund projects(Youth Project)of the Educational Department of Liaoning Province in 2023(Grants No.JYTQN2023451)Liaoning Institute of Science and Technology doctoral research initiation fund project in 2023(Grants No.2307B27)+2 种基金Basic Research Project of Higher Education Institutions of Liaoning Provincial Department of Education(Grants No.2024JYTYB-12)the Basic scientific research fund projects(Youth Project)of the Educational Department of Liaoning Province in 2023(Grants No.JYTQN2024-21)Liaoning Institute of Science and Technology doctoral research initiation fund project in 2023(Grants No.2307B26)。
文摘The estimation of glacier flow velocity on a short-term scale is very important for further glacier dynamics research.In this study,10 Sentinel-1 ascending images and 10 Sentinel-1 descending images of Urumqi Glacier No.1 in 2017 were used to calculate the glacier flow velocity in a high coherence period by DIn SAR technology and MAI technology,while the offset tracking technology was used to estimate the glacier flow velocity in a low coherence period.Then,the monthly three-dimensional flow velocity of the glacier was calculated by the Helmert variance component estimation method.Finally,the accuracy of the estimated glacier flow velocity on a monthly scale was evaluated.The results showed that:(1)the monthly scale motion velocity of Urumqi Glacier No.1 in May,June,July,and August 2017 was 0.273 m/month,0.657 m/month,0.582 m/month,and 0.392 m/month,respectively.(2)The accuracy of glacier surface velocity from May 2017 to August 2017 was 0.033 m/month,0.026 m/month,0.034 m/month and 0.037 m/month,respectively.(3)The accuracy of glacier surface flow velocity from May 2017 to August 2017 was 0.018 m/month,0.031 m/month,0.029 m/month and 0.030 m/month,respectively.Therefore,the research methodology based on the Sentinel-1 ascending and descending data and presented in this paper was applicable to the estimation of monthly-scale flow velocity of mountain glaciers.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant 42071454 and Grant 42371466the State Key Laboratory of Geo-Information Engineering under Grant SKLGIE2023-M-2-2.
文摘Navigation technology,which integrates vision,Inertial Measurement Unit(IMU),and Ultra-Wideband(UWB)sensors in GNSS-denied environments has gained a significant attention.However,inaccurate estimation of UWB anchor positions and improper sensor weighting among heterogeneous sensors significantly impairs the positioning accuracy and robustness of Visual-Inertial-UWB(VIU)systems.To accurately and rapidly estimate the UWB anchor positions,we employed the robust ridge nonlinear least-squares method to improve the accuracy and reliability of the estimated UWB anchor position.Additionally,we proposed a simple and effective method to assess the accuracy of the UWB anchor position using the geometric dilution precision principle,which facilitates rapid and accurate estimation of the UWB anchor position.Furthermore,we designed a method to calculate the estimated UWB anchor position error in real-world settings.Finally,we proposed a nonlinear optimization method with dynamically adaptive weighting based on the HELMERT variance component estimation principle,which assigns appropriate weights to heterogeneous sensors.To validate the feasibility and effectiveness of the proposed method,comprehensive simulations and real-world experiments were conducted.First,using Monte Carlo simulation and real-world experiments,we validated the effectiveness of the proposed methods for UWB anchor position and its accuracy estimation.Then,we conducted ablation experiments utilizing the open-source VIRAL and real-world datasets.The experimental results demonstrate that the proposed method exhibits superior positioning accuracy and robustness in contrast to the open-source VINS-MONO and VIR-SLAM methods.
