1.The need for global carbon monitoring from space and the TanSat mission Global warming is a major problem,for which carbon dioxide（CO2 ）is the main greenhouse gas involved in heating the troposphere.However,the po...1.The need for global carbon monitoring from space and the TanSat mission Global warming is a major problem,for which carbon dioxide（CO2 ）is the main greenhouse gas involved in heating the troposphere.However,the poor availability of global CO2 measurements makes it difficult to estimate CO2 emissions accurately.展开更多
The group-delay dispersion of an optical fiber was measured with the time-of-flight method, using fingerprint-like characteristic spectra from a mode-locked fiber laser source. To determine the group-delay dispersion ...The group-delay dispersion of an optical fiber was measured with the time-of-flight method, using fingerprint-like characteristic spectra from a mode-locked fiber laser source. To determine the group-delay dispersion up to the fourth order, least-squares fitting was applied to the overall time waveform mapped on the time axis for the fingerprint-spectral broadband pulses through a long optical fiber. The analysis of all 4003 data points reduced statistical uncertainty, and provided second-, third-, and fourth-order dispersion with uncertainties of 0.02%, 0.4%, and 4%,respectively.展开更多
Let(E,H,μ)be an abstract Wiener spacein the sense of L.Gross.It is proved that if u is a measurable map from E to H such that u∈W 2.1(H,μ)and there exists a constantα,0<α<1,such that either∑n‖D nu(w)‖2 H...Let(E,H,μ)be an abstract Wiener spacein the sense of L.Gross.It is proved that if u is a measurable map from E to H such that u∈W 2.1(H,μ)and there exists a constantα,0<α<1,such that either∑n‖D nu(w)‖2 Hα2 a.s.or‖u(w+h)-u(w)‖Hα‖h‖H a.s.for every h∈H and E exp108(1-α)2∑‖D n u‖H)<∞,then the measureμT-1 is equivalent toμ,where T(w)=w+u(w)for w∈E.And the explicit expression of the Radon-Nikodym derivative(cf.Theorem 2.1)is given.展开更多
This paper presents a hierarchical simultaneous localization and mapping（SLAM） system for a small unmanned aerial vehicle（UAV） using the output of an inertial measurement unit（IMU） and the bearing-only observati...This paper presents a hierarchical simultaneous localization and mapping（SLAM） system for a small unmanned aerial vehicle（UAV） using the output of an inertial measurement unit（IMU） and the bearing-only observations from an onboard monocular camera.A homography based approach is used to calculate the motion of the vehicle in 6 degrees of freedom by image feature match.This visual measurement is fused with the inertial outputs by an indirect extended Kalman filter（EKF） for attitude and velocity estimation.Then,another EKF is employed to estimate the position of the vehicle and the locations of the features in the map.Both simulations and experiments are carried out to test the performance of the proposed system.The result of the comparison with the referential global positioning system/inertial navigation system（GPS/INS） navigation indicates that the proposed SLAM can provide reliable and stable state estimation for small UAVs in GPS-denied environments.展开更多
基金supported by the National Key R&D Program of China (2016YFA0600203)the National High-Tech Research and Development Program (2011AA12A104)External Cooperation Program of the Chinese Academy of Sci-ences (Grant No. GJHZ1507)
文摘1.The need for global carbon monitoring from space and the TanSat mission Global warming is a major problem,for which carbon dioxide（CO2 ）is the main greenhouse gas involved in heating the troposphere.However,the poor availability of global CO2 measurements makes it difficult to estimate CO2 emissions accurately.
基金partly supported by KAKENHI No. 15H03968 and No. 26610081 from JSPS, the Photon Frontier Network Program of MEXT, JST-SENTAN, and JST-CREST in Japanthe European Regional Development Fund+1 种基金the European Social Fundthe state budget of the Czech Republic (project HiLASE: CZ.1.05/2.1.00/01.0027, project Postdok: CZ.1.07/2.3.00/30.0057)
文摘The group-delay dispersion of an optical fiber was measured with the time-of-flight method, using fingerprint-like characteristic spectra from a mode-locked fiber laser source. To determine the group-delay dispersion up to the fourth order, least-squares fitting was applied to the overall time waveform mapped on the time axis for the fingerprint-spectral broadband pulses through a long optical fiber. The analysis of all 4003 data points reduced statistical uncertainty, and provided second-, third-, and fourth-order dispersion with uncertainties of 0.02%, 0.4%, and 4%,respectively.
文摘Let(E,H,μ)be an abstract Wiener spacein the sense of L.Gross.It is proved that if u is a measurable map from E to H such that u∈W 2.1(H,μ)and there exists a constantα,0<α<1,such that either∑n‖D nu(w)‖2 Hα2 a.s.or‖u(w+h)-u(w)‖Hα‖h‖H a.s.for every h∈H and E exp108(1-α)2∑‖D n u‖H)<∞,then the measureμT-1 is equivalent toμ,where T(w)=w+u(w)for w∈E.And the explicit expression of the Radon-Nikodym derivative(cf.Theorem 2.1)is given.
基金supported by National High Technology Research Development Program of China (863 Program) (No.2011AA040202)National Science Foundation of China (No.51005008)
文摘This paper presents a hierarchical simultaneous localization and mapping（SLAM） system for a small unmanned aerial vehicle（UAV） using the output of an inertial measurement unit（IMU） and the bearing-only observations from an onboard monocular camera.A homography based approach is used to calculate the motion of the vehicle in 6 degrees of freedom by image feature match.This visual measurement is fused with the inertial outputs by an indirect extended Kalman filter（EKF） for attitude and velocity estimation.Then,another EKF is employed to estimate the position of the vehicle and the locations of the features in the map.Both simulations and experiments are carried out to test the performance of the proposed system.The result of the comparison with the referential global positioning system/inertial navigation system（GPS/INS） navigation indicates that the proposed SLAM can provide reliable and stable state estimation for small UAVs in GPS-denied environments.
