The time-frequency analysis of the signal acquired by a single ground-based microphone shows a two-dimensional interference pattern in the time-frequency plane,which is caused by the time delay of the received signal ...The time-frequency analysis of the signal acquired by a single ground-based microphone shows a two-dimensional interference pattern in the time-frequency plane,which is caused by the time delay of the received signal emitted from a low flying aircraft via the direct path and the ground-re-flected path. A model is developed for estimating the motion parameters of an aircraft flying along a straight line at a constant height and with a constant speed. Monte Carlo simulation results and ex-perimental results are presented to validate the model,and an error analysis of the model is presented to verify the effectiveness of the estimation scheme advocated.展开更多
Under single-satellite observation,the parameter estimation of the boost phase of high-precision space noncooperative targets requires prior information.To improve the accuracy without prior information,we propose a p...Under single-satellite observation,the parameter estimation of the boost phase of high-precision space noncooperative targets requires prior information.To improve the accuracy without prior information,we propose a parameter estimation model of the boost phase based on trajectory plane parametric cutting.The use of the plane passing through the geo-center and the cutting sequence line of sight(LOS)generates the trajectory-cutting plane.With the coefficient of the trajectory cutting plane directly used as the parameter to be estimated,a motion parameter estimation model in space non-cooperative targets is established,and the Gauss-Newton iteration method is used to solve the flight parameters.The experimental results show that the estimation algorithm proposed in this paper weakly relies on prior information and has higher estimation accuracy,providing a practical new idea and method for the parameter estimation of space non-cooperative targets under single-satellite warning.展开更多
The pantograph transfers electric energy from the catenary to high-speed trains and is critical for electrified railways.However,excessive motion can cause pantograph-catenary malfunctions,including catenary breaks,ar...The pantograph transfers electric energy from the catenary to high-speed trains and is critical for electrified railways.However,excessive motion can cause pantograph-catenary malfunctions,including catenary breaks,arcing,and mechanical damage to the pantograph.Therefore,detecting pantograph head motion is crucial for reliable high-speed train operation.This paper employs an improved Siamese network to measure its horizontal/vertical displacement and estimate the dynamic envelope.A multi-branch Siamese network is also developed to extract displacements of multiple targets for stagger value estimation.Additionally,the proposed MOTFSE algorithm(Multi-Object Tracking and Optical Flow Speed Estimation)fuses tracking and optical flow results to estimate the vertical vibration speed.Experimental results show the proposed algorithm achieves over 90%tracking accuracy and precision for the pantograph head.It enables accurate measurement of the pantograph's dynamic envelope,contact wire stagger value,and head vertical oscillation velocity,offering a viable solution for practical application.展开更多
文摘The time-frequency analysis of the signal acquired by a single ground-based microphone shows a two-dimensional interference pattern in the time-frequency plane,which is caused by the time delay of the received signal emitted from a low flying aircraft via the direct path and the ground-re-flected path. A model is developed for estimating the motion parameters of an aircraft flying along a straight line at a constant height and with a constant speed. Monte Carlo simulation results and ex-perimental results are presented to validate the model,and an error analysis of the model is presented to verify the effectiveness of the estimation scheme advocated.
基金supported in part by the National Natural Science Foundation of China(Nos.42271448,41701531)the Key Laboratory of Land Satellite Remote Sensing Application,Ministry of Natural Resources of the People’s Republic of China(No.KLSMNRG202317)。
文摘Under single-satellite observation,the parameter estimation of the boost phase of high-precision space noncooperative targets requires prior information.To improve the accuracy without prior information,we propose a parameter estimation model of the boost phase based on trajectory plane parametric cutting.The use of the plane passing through the geo-center and the cutting sequence line of sight(LOS)generates the trajectory-cutting plane.With the coefficient of the trajectory cutting plane directly used as the parameter to be estimated,a motion parameter estimation model in space non-cooperative targets is established,and the Gauss-Newton iteration method is used to solve the flight parameters.The experimental results show that the estimation algorithm proposed in this paper weakly relies on prior information and has higher estimation accuracy,providing a practical new idea and method for the parameter estimation of space non-cooperative targets under single-satellite warning.
基金supported in part by the Open Fund of the Key State Laboratory of High-Speed Maglev Transportation Technology under grant number SKLM-SFCF-2024-004in part by the Frontiers Science Center for Smart High-speed Railway System under grant number 2022JBQY007。
文摘The pantograph transfers electric energy from the catenary to high-speed trains and is critical for electrified railways.However,excessive motion can cause pantograph-catenary malfunctions,including catenary breaks,arcing,and mechanical damage to the pantograph.Therefore,detecting pantograph head motion is crucial for reliable high-speed train operation.This paper employs an improved Siamese network to measure its horizontal/vertical displacement and estimate the dynamic envelope.A multi-branch Siamese network is also developed to extract displacements of multiple targets for stagger value estimation.Additionally,the proposed MOTFSE algorithm(Multi-Object Tracking and Optical Flow Speed Estimation)fuses tracking and optical flow results to estimate the vertical vibration speed.Experimental results show the proposed algorithm achieves over 90%tracking accuracy and precision for the pantograph head.It enables accurate measurement of the pantograph's dynamic envelope,contact wire stagger value,and head vertical oscillation velocity,offering a viable solution for practical application.
