Atmospheric turbulence is an important parameter affecting laser atmospheric transmission.This paper reports on a self-developed atmospheric turbulence detection Li DAR system(scanning differential image motion Li DAR...Atmospheric turbulence is an important parameter affecting laser atmospheric transmission.This paper reports on a self-developed atmospheric turbulence detection Li DAR system(scanning differential image motion Li DAR(DIM-Li DAR)system).By designing and simulating the optical system of atmospheric turbulence detection Li DAR,the basic optical imaging accuracy has been determined.展开更多
A robust nonsingular fixed time terminal sliding mode control scheme with a time delay disturbance observer is proposed for atmospheric pollution detection lidar scanning mechanism(APDL-SM)system.Distinguished from th...A robust nonsingular fixed time terminal sliding mode control scheme with a time delay disturbance observer is proposed for atmospheric pollution detection lidar scanning mechanism(APDL-SM)system.Distinguished from the conventional terminal sliding mode control methods,the authors design a novel fixed-time terminal sliding surface,the convergence time of sliding mode phase of which has a constant upper bound that is designable by adjusting only one parameter.Moreover,in order to overcome the problem of unknown upper bound of lumped uncertainty including model uncertainty,friction effect and external disturbances from the port environment,the authors propose a time delay disturbance observer to provide an estimation for the system lumped uncertainty.By using the Lyapunov synthesis,the explicit analysis of the convergence time upper bound are performed.Finally,simulation studies are conducted on the APDL-SM system to show the fast convergence rate and strong robustness of the proposed control scheme.展开更多
By detecting the severe meteorological situations on flight route,airborne weather radar(WXR)can ensure the safety of the aircraft and on-board personnel.Among these critical weather conditions,atmospheric turbulence ...By detecting the severe meteorological situations on flight route,airborne weather radar(WXR)can ensure the safety of the aircraft and on-board personnel.Among these critical weather conditions,atmospheric turbulence is one of the main factors that affect flight safety.Atmospheric turbulence detection method that the current WXR adopts mainly is the pulse pair processing(PPP)method,which estimates Doppler spectrum width of weather target echo and compares it with a threshold to determine whether this weather target is turbulence or not.PPP method is simple and easy to implement,but the performance of this method under the condition of low signal-to-noise ratio(SNR)is poor.In this paper,we propose a new turbulence detection method based on the principal component analysis(PCA)approach.This new method uses PCA approach to preprocess the weather target echo and divides it into two parts:the principal component part as signal and the rest part as noise,so as to realize the de-noising function of PCA approach,and it is then combined with PPP method to estimate the spectrum width.Due to the good de-noising performance of PCA approach,this new method improves the detection performance of traditional PPP method especially under the condition of low SNR.展开更多
It is of great significance to develop a high-precision and high spatiotemporal resolution of stereoscopic detection technology to finely delineate the horizontal and vertical distributions of CO_(2).This study elabor...It is of great significance to develop a high-precision and high spatiotemporal resolution of stereoscopic detection technology to finely delineate the horizontal and vertical distributions of CO_(2).This study elaborates on the superiorities of single photon spectroscopy,key steps to develop a high-performance single photon LIDAR,and their potential applications.Single-photon CO_(2)LIDAR integrates quantum sensing techniques with classical spectral measurement techniques,and can overcome the detection limitations of traditional CO_(2)LIDAR in terms of detection distance,sensitivity,and spatiotemporal resolution.We anticipate that the single-photon spectroscopic technology can be widely applied in the detection of regional distribution and emission fluxes of CO_(2),transboundary transport fluxes of CO_(2),and in supporting the establishment of a new carbon monitoring framework.展开更多
基金jointly funded by the National Science Foundation of China(No.42405069)the University Natural Sciences Research Project of Anhui Province(Nos.2023AH052201 and 2023AH052184)+1 种基金the 2023 Talent Research Fund Project of Hefei University(No.23RC01)the Technical Development Project of Hefei University(Nos.902/22050124128,902/22050124148 and 902/22050124250)。
文摘Atmospheric turbulence is an important parameter affecting laser atmospheric transmission.This paper reports on a self-developed atmospheric turbulence detection Li DAR system(scanning differential image motion Li DAR(DIM-Li DAR)system).By designing and simulating the optical system of atmospheric turbulence detection Li DAR,the basic optical imaging accuracy has been determined.
基金supported by the National Key Research and Development Project of China under Grant Nos.2018AAA0100800 and 2018YFE0106800the National Natural Science Foundation of China under Grant Nos.61903353,61725304,and 1761673361+2 种基金Major Science and Technology Project of Anhui Province under Grant No.912198698036SINOPEC Programmes for Science and Technology Development under Grant No.PE19008-8the Fundamental Research Funds for the Central Universities under Grant No.WK2100000013。
文摘A robust nonsingular fixed time terminal sliding mode control scheme with a time delay disturbance observer is proposed for atmospheric pollution detection lidar scanning mechanism(APDL-SM)system.Distinguished from the conventional terminal sliding mode control methods,the authors design a novel fixed-time terminal sliding surface,the convergence time of sliding mode phase of which has a constant upper bound that is designable by adjusting only one parameter.Moreover,in order to overcome the problem of unknown upper bound of lumped uncertainty including model uncertainty,friction effect and external disturbances from the port environment,the authors propose a time delay disturbance observer to provide an estimation for the system lumped uncertainty.By using the Lyapunov synthesis,the explicit analysis of the convergence time upper bound are performed.Finally,simulation studies are conducted on the APDL-SM system to show the fast convergence rate and strong robustness of the proposed control scheme.
基金sponsored by National Program on Key Basic Research Project(2014CB744903)National Natural Science Foundation of China(61673270)+3 种基金Shanghai Pujiang Program(16PJD028)Shanghai Industrial Strengthening Project(GYQJ-2017-5-08)Shanghai Science and Technology Committee Research Project(17DZ1204304)Shanghai Engineering Research Center of Civil Aircraft Flight Testing.
文摘By detecting the severe meteorological situations on flight route,airborne weather radar(WXR)can ensure the safety of the aircraft and on-board personnel.Among these critical weather conditions,atmospheric turbulence is one of the main factors that affect flight safety.Atmospheric turbulence detection method that the current WXR adopts mainly is the pulse pair processing(PPP)method,which estimates Doppler spectrum width of weather target echo and compares it with a threshold to determine whether this weather target is turbulence or not.PPP method is simple and easy to implement,but the performance of this method under the condition of low signal-to-noise ratio(SNR)is poor.In this paper,we propose a new turbulence detection method based on the principal component analysis(PCA)approach.This new method uses PCA approach to preprocess the weather target echo and divides it into two parts:the principal component part as signal and the rest part as noise,so as to realize the de-noising function of PCA approach,and it is then combined with PPP method to estimate the spectrum width.Due to the good de-noising performance of PCA approach,this new method improves the detection performance of traditional PPP method especially under the condition of low SNR.
基金supported by Excellent Young Scientists Fund of the National Natural Science Foundation of China(62322514,62322513)National Science Foundation of China(12174367)+1 种基金Anhui Science Fund for Distinguished Young Scholars(2308085J25)National Key Research and Development Program of China(2023YFC3709502,2022YFC3700100).
文摘It is of great significance to develop a high-precision and high spatiotemporal resolution of stereoscopic detection technology to finely delineate the horizontal and vertical distributions of CO_(2).This study elaborates on the superiorities of single photon spectroscopy,key steps to develop a high-performance single photon LIDAR,and their potential applications.Single-photon CO_(2)LIDAR integrates quantum sensing techniques with classical spectral measurement techniques,and can overcome the detection limitations of traditional CO_(2)LIDAR in terms of detection distance,sensitivity,and spatiotemporal resolution.We anticipate that the single-photon spectroscopic technology can be widely applied in the detection of regional distribution and emission fluxes of CO_(2),transboundary transport fluxes of CO_(2),and in supporting the establishment of a new carbon monitoring framework.
