We propose a novel method of slice image reconstruction with controllable spatial filtering by using the correlation of periodic delta-function arrays （PDFAs） with elemental images in computational integral imaging....We propose a novel method of slice image reconstruction with controllable spatial filtering by using the correlation of periodic delta-function arrays （PDFAs） with elemental images in computational integral imaging. The multiple PDFAs, whose spatial periods correspond to object＇s depths with the elemental image array （EIA）, can generate a set of spatially filtered EIAs for multiple object depths compared with the conventional method for the depth of a single object. We analyze a controllable spatial filtering effect by the proposed method. To show the feasibility of the proposed method, we carry out preliminary experiments for multiple objects and present the results.展开更多
In view of the requirements of Tianwen-1 missions on precision orbit determination and scientific application,this paper proposes a high-precision open-loop velocity measurement method based on ground-based radio.At f...In view of the requirements of Tianwen-1 missions on precision orbit determination and scientific application,this paper proposes a high-precision open-loop velocity measurement method based on ground-based radio.At first,relying on space–ground TT&C resources of the Tianwen-1 probe,the paper designs an open-loop velocity measurement strategy based on China’s deep-space network.Then,it proposes a core algorithm of open-loop velocity measurement based on local cross-correlation reconstruction to obtain instantaneous Doppler frequency observables.This algorithm is characterized by a high ability to avoid phase lock loss,convenient and efficient implementation,and flexible parameter configuration and is suitable for high-precision velocity measurement in the case of high dynamics and low signal-to-noise ratios.On this basis,the similarity and difference of velocity observables between open-loop and baseband velocity measurements are analyzed comparatively.Finally,on the basis of the open-loop velocity measurement method,the paper carries out tests on high precision orbit determination with independent support of velocity measurement,as well as on Mars radio occultation.According to the research results,the accuracy of open-loop velocity measurement can reach 0.05 mm/s(in 1-s integration time),which is 2 to 3 times better than that of baseband velocity measurement.Open-loop velocity measurement can independently support orbit determination accuracy of 50 m of the Tianwen-1 probe and effectively support autonomous retrieval of Martian ionospheric electron density profiles.Thus,this method can be effectively applied to future missions of deep-space exploration and research of planetary radio science.展开更多
基金supported by the information technology(IT)research and development program of MKE/KEIT(10041682Development of High-Definition 3D Image Processing Technologies Using Advanced Integral Imaging with Improved Depth Range)
文摘We propose a novel method of slice image reconstruction with controllable spatial filtering by using the correlation of periodic delta-function arrays （PDFAs） with elemental images in computational integral imaging. The multiple PDFAs, whose spatial periods correspond to object＇s depths with the elemental image array （EIA）, can generate a set of spatially filtered EIAs for multiple object depths compared with the conventional method for the depth of a single object. We analyze a controllable spatial filtering effect by the proposed method. To show the feasibility of the proposed method, we carry out preliminary experiments for multiple objects and present the results.
基金supported by the National Natural Science Foundation of China(nos.11973015 and 12373082)Civil Aerospace Research Project of China(no.D020309)National Key Laboratory of Aerospace Flight Dynamics(no.KGJ6142210220106).
文摘In view of the requirements of Tianwen-1 missions on precision orbit determination and scientific application,this paper proposes a high-precision open-loop velocity measurement method based on ground-based radio.At first,relying on space–ground TT&C resources of the Tianwen-1 probe,the paper designs an open-loop velocity measurement strategy based on China’s deep-space network.Then,it proposes a core algorithm of open-loop velocity measurement based on local cross-correlation reconstruction to obtain instantaneous Doppler frequency observables.This algorithm is characterized by a high ability to avoid phase lock loss,convenient and efficient implementation,and flexible parameter configuration and is suitable for high-precision velocity measurement in the case of high dynamics and low signal-to-noise ratios.On this basis,the similarity and difference of velocity observables between open-loop and baseband velocity measurements are analyzed comparatively.Finally,on the basis of the open-loop velocity measurement method,the paper carries out tests on high precision orbit determination with independent support of velocity measurement,as well as on Mars radio occultation.According to the research results,the accuracy of open-loop velocity measurement can reach 0.05 mm/s(in 1-s integration time),which is 2 to 3 times better than that of baseband velocity measurement.Open-loop velocity measurement can independently support orbit determination accuracy of 50 m of the Tianwen-1 probe and effectively support autonomous retrieval of Martian ionospheric electron density profiles.Thus,this method can be effectively applied to future missions of deep-space exploration and research of planetary radio science.
