At 07:51 Beijing time on December22,a LM-11 launch vehicle soared up from the Jiuquan Satellite Launch Center,placing the first satellite of the Hongyun Project into orbit.Developed by the China Academy of Launch Vehi...At 07:51 Beijing time on December22,a LM-11 launch vehicle soared up from the Jiuquan Satellite Launch Center,placing the first satellite of the Hongyun Project into orbit.Developed by the China Academy of Launch Vehicle Technology,LM-11 is the first solid launch vehicle among the LMlaunch vehicle family,as well as the only solid carrier rocket of China’s new-generation launch vehicles.It features flexible use,continuous and multiple launches with high-density.展开更多
Satellite communications is not only a key technical for students who major in information subject must know well, but also a satellite cultural background course at the information age. Based on the current situation...Satellite communications is not only a key technical for students who major in information subject must know well, but also a satellite cultural background course at the information age. Based on the current situation and characteristics of Universities of 211 Project, such as teaching objectives, course settings, and too much categories of professional courses but class hour reduced. From the point of view of teaching contents and methods, the reform contents and the characteristic requirements of the satellite communications course are presented, especially, the proposed reform to satellite communications materials and experimental content can meet the needs of the new times.展开更多
Based on the high energy γ-ray yield from the H-bomb D-T fusion reaction, it brings forward the idea applying the 16.76 MeV γ-ray to judge whether the H-bomb happens or not, and to deduce the explosion TNT equivalen...Based on the high energy γ-ray yield from the H-bomb D-T fusion reaction, it brings forward the idea applying the 16.76 MeV γ-ray to judge whether the H-bomb happens or not, and to deduce the explosion TNT equivalent accurately. The Monte Carlo N-Particle was applied to simulate the high energy γ-ray radiation characteristics reaching the geosynchronous orbit satellite, and the CVD diamond detector suit for the requirements was researched. A series of experiments were carried out to testify the capabilities of the diamond detector. It provides a brand-new approach to satellite-based nuclear explosion detection.展开更多
A novel subspace projection anti-jamming algorithm based on spatial blind search is proposed,which uses multiple single-constrained subspace projection parallel filters.If the direction of arrival(DOA)of a satellite s...A novel subspace projection anti-jamming algorithm based on spatial blind search is proposed,which uses multiple single-constrained subspace projection parallel filters.If the direction of arrival(DOA)of a satellite signal is unknown,the traditional subspace projection anti-jamming algorithm cannot form the correct beam pointing.To overcome the problem of the traditional subspace projection algorithm,multiple single-constrained subspace projection parallel filters are used.Every single-constrained anti-jamming subspace projection algorithm obtains the optimal weight vector by searching the DOA of the satellite signal and uses the output of cross correlation as a decision criterion.Test results show that the algorithm can suppress the jamming effectively,and generate high gain toward the desired signal.The research provides a new idea for the engineering implementation of a multi-beam anti-jamming algorithm based on subspace projection.展开更多
Snow depth over sea ice is an essential variable for understanding the Arctic energy budget.In this study,we evaluate snow depth over Arctic sea ice during 1993-2014 simulated by 31 models from phase 6 of the Coupled ...Snow depth over sea ice is an essential variable for understanding the Arctic energy budget.In this study,we evaluate snow depth over Arctic sea ice during 1993-2014 simulated by 31 models from phase 6 of the Coupled Model Intercomparison Project(CMIP6)against recent satellite retrievals.The CMIP6 models capture some aspects of the observed snow depth climatology and variability.The observed variability lies in the middle of the models’simulations.All the models show negative trends of snow depth during 1993-2014.However,substantial spatiotemporal discrepancies are identified.Compared to the observation,most models have late seasonal maximum snow depth(by two months),remarkably thinner snow for the seasonal minimum,an incorrect transition from the growth to decay period,and a greatly underestimated interannual variability and thinning trend of snow depth over areas with frequent occurrence of multi-year sea ice.Most models are unable to reproduce the observed snow depth gradient from the Canadian Arctic to the outer areas and the largest thinning rate in the central Arctic.Future projections suggest that snow depth in the Arctic will continue to decrease from 2015 to 2099.Under the SSP5-8.5 scenario,the Arctic will be almost snow-free during the summer and fall and the accumulation of snow starts from January.Further investigation into the possible causes of the issues for the simulated snow depth by some models based on the same family of models suggests that resolution,the inclusion of a hightop atmospheric model,and biogeochemistry processes are important factors for snow depth simulation.展开更多
Surface observations and CHAMP measurement data are employed to develop a three-dimensional surface spline(3DSS)model of China's Mainland.The magnetic field distribution at the satellite level is then demonstrated...Surface observations and CHAMP measurement data are employed to develop a three-dimensional surface spline(3DSS)model of China's Mainland.The magnetic field distribution at the satellite level is then demonstrated using the model obtained.The results of this model are compared and verifi ed by deriving the corresponding two(2DTY)and threedimensional(3DTY)Taylor polynomial models.Issues such as the removal of disruptive geomagnetic fi elds,the data gap between the surface and satellite levels,and boundary eff ects are carefully considered during modeling.We then focus on evaluating the modeling eff ect of the satellite data.Ten satellite points not involved in the modeling procedure are selected,and the residuals,absolute change rates,and RMSEs of these points are calculated.Results show that the distribution of the magnetic fi eld determined by the 3DSS model is highly consistent with that obtained from the IGRF12 model.Expect for component Y,the absolute change rates of other components are less than 0.5%.Specifi cally,the RMSE of Y of 3DSS is nearly 60%lower than those of 3DTY and 2DTY;the RMSE of other components of the former are also over 90%lower than those of the latter.This fi nding implies that the 3DSS model has good performance for modeling satellite data and its results are reliable.Moreover,the modeling eff ect of 3DTY is better than that of 2DTY.展开更多
China Asia-Pacific Mobile Telecommunications Satellite Co., Ltd. (China APMT) has signed a QB50 Project Memorandum of Understanding with the Von Karman Institute for Fluid Dynamics (VKI). According to the agreement, C...China Asia-Pacific Mobile Telecommunications Satellite Co., Ltd. (China APMT) has signed a QB50 Project Memorandum of Understanding with the Von Karman Institute for Fluid Dynamics (VKI). According to the agreement, China APMT will launch 50 miniaturized satellites for VKI from 2014-15.展开更多
The Par-Tapi-Narmada river link envisages transfer of surplus water from west flowing rivers between Par and Tapi in Gujarat State, India to water deficit areas in North Gujarat. The scheme is located mainly in southe...The Par-Tapi-Narmada river link envisages transfer of surplus water from west flowing rivers between Par and Tapi in Gujarat State, India to water deficit areas in North Gujarat. The scheme is located mainly in southern Gujarat but it also covers part of the areas of Maharashtra, North of Mumbai on the Western Ghats of India. The main aim of Par-Tapi-Narmada link is to transfer the surplus waters of Par, Auranga, Ambica and Purna River basins to take over part of Narmada Canal command (Miyagam branch) after providing enroute irrigation. It is proposed that water saved in Sardar Sarovar Project, as a result of this transfer, would be taken further northwards to benefit water scarce areas of north Gujarat and also westwards in Saurashtra and Kutch regions. The construction of seven reservoirs on Par-Tapi-Narmada River Link Project would affect land use/land cover, settlements and infrastructure facilities within and around reservoir area. Thus, the submergence impact analysis of all the seven reservoirs of this project have been carried out by using remote sensing and GIS techniques for planning and designing of the structures. Out of the seven reservoirs, the paper discusses submergence analysis of Kelwan Dam reservoir which is located in geologically complex region of the Dangs district. The study attempts to assess the present problems of submergence of land, forest, agriculture, settlements and infrastructure facilities by using GIS techniques for taking alternative remedial measures prior and during construction of the dams.展开更多
文摘At 07:51 Beijing time on December22,a LM-11 launch vehicle soared up from the Jiuquan Satellite Launch Center,placing the first satellite of the Hongyun Project into orbit.Developed by the China Academy of Launch Vehicle Technology,LM-11 is the first solid launch vehicle among the LMlaunch vehicle family,as well as the only solid carrier rocket of China’s new-generation launch vehicles.It features flexible use,continuous and multiple launches with high-density.
文摘Satellite communications is not only a key technical for students who major in information subject must know well, but also a satellite cultural background course at the information age. Based on the current situation and characteristics of Universities of 211 Project, such as teaching objectives, course settings, and too much categories of professional courses but class hour reduced. From the point of view of teaching contents and methods, the reform contents and the characteristic requirements of the satellite communications course are presented, especially, the proposed reform to satellite communications materials and experimental content can meet the needs of the new times.
文摘Based on the high energy γ-ray yield from the H-bomb D-T fusion reaction, it brings forward the idea applying the 16.76 MeV γ-ray to judge whether the H-bomb happens or not, and to deduce the explosion TNT equivalent accurately. The Monte Carlo N-Particle was applied to simulate the high energy γ-ray radiation characteristics reaching the geosynchronous orbit satellite, and the CVD diamond detector suit for the requirements was researched. A series of experiments were carried out to testify the capabilities of the diamond detector. It provides a brand-new approach to satellite-based nuclear explosion detection.
基金Supported by the Natural Science Foundation of Hebei Province(F2011205023)the National Natural Science Foundation of China(61175059)。
文摘A novel subspace projection anti-jamming algorithm based on spatial blind search is proposed,which uses multiple single-constrained subspace projection parallel filters.If the direction of arrival(DOA)of a satellite signal is unknown,the traditional subspace projection anti-jamming algorithm cannot form the correct beam pointing.To overcome the problem of the traditional subspace projection algorithm,multiple single-constrained subspace projection parallel filters are used.Every single-constrained anti-jamming subspace projection algorithm obtains the optimal weight vector by searching the DOA of the satellite signal and uses the output of cross correlation as a decision criterion.Test results show that the algorithm can suppress the jamming effectively,and generate high gain toward the desired signal.The research provides a new idea for the engineering implementation of a multi-beam anti-jamming algorithm based on subspace projection.
基金supported by the NOAA Climate Program Office(Grant No.NA15OAR4310163)the National Key R&D Program of China(Grant Nos.2018YFA0605904 and 2018YFA0605901)the National Natural Science Foundation of China(Grant No.41676185)。
文摘Snow depth over sea ice is an essential variable for understanding the Arctic energy budget.In this study,we evaluate snow depth over Arctic sea ice during 1993-2014 simulated by 31 models from phase 6 of the Coupled Model Intercomparison Project(CMIP6)against recent satellite retrievals.The CMIP6 models capture some aspects of the observed snow depth climatology and variability.The observed variability lies in the middle of the models’simulations.All the models show negative trends of snow depth during 1993-2014.However,substantial spatiotemporal discrepancies are identified.Compared to the observation,most models have late seasonal maximum snow depth(by two months),remarkably thinner snow for the seasonal minimum,an incorrect transition from the growth to decay period,and a greatly underestimated interannual variability and thinning trend of snow depth over areas with frequent occurrence of multi-year sea ice.Most models are unable to reproduce the observed snow depth gradient from the Canadian Arctic to the outer areas and the largest thinning rate in the central Arctic.Future projections suggest that snow depth in the Arctic will continue to decrease from 2015 to 2099.Under the SSP5-8.5 scenario,the Arctic will be almost snow-free during the summer and fall and the accumulation of snow starts from January.Further investigation into the possible causes of the issues for the simulated snow depth by some models based on the same family of models suggests that resolution,the inclusion of a hightop atmospheric model,and biogeochemistry processes are important factors for snow depth simulation.
基金This work was supported by the National Natural Science Foundation of China(Nos.41974073,41404053)Special Project for Meteo-Scientifi c Research in the Public Interest(No.GYHY201306073)。
文摘Surface observations and CHAMP measurement data are employed to develop a three-dimensional surface spline(3DSS)model of China's Mainland.The magnetic field distribution at the satellite level is then demonstrated using the model obtained.The results of this model are compared and verifi ed by deriving the corresponding two(2DTY)and threedimensional(3DTY)Taylor polynomial models.Issues such as the removal of disruptive geomagnetic fi elds,the data gap between the surface and satellite levels,and boundary eff ects are carefully considered during modeling.We then focus on evaluating the modeling eff ect of the satellite data.Ten satellite points not involved in the modeling procedure are selected,and the residuals,absolute change rates,and RMSEs of these points are calculated.Results show that the distribution of the magnetic fi eld determined by the 3DSS model is highly consistent with that obtained from the IGRF12 model.Expect for component Y,the absolute change rates of other components are less than 0.5%.Specifi cally,the RMSE of Y of 3DSS is nearly 60%lower than those of 3DTY and 2DTY;the RMSE of other components of the former are also over 90%lower than those of the latter.This fi nding implies that the 3DSS model has good performance for modeling satellite data and its results are reliable.Moreover,the modeling eff ect of 3DTY is better than that of 2DTY.
文摘China Asia-Pacific Mobile Telecommunications Satellite Co., Ltd. (China APMT) has signed a QB50 Project Memorandum of Understanding with the Von Karman Institute for Fluid Dynamics (VKI). According to the agreement, China APMT will launch 50 miniaturized satellites for VKI from 2014-15.
文摘The Par-Tapi-Narmada river link envisages transfer of surplus water from west flowing rivers between Par and Tapi in Gujarat State, India to water deficit areas in North Gujarat. The scheme is located mainly in southern Gujarat but it also covers part of the areas of Maharashtra, North of Mumbai on the Western Ghats of India. The main aim of Par-Tapi-Narmada link is to transfer the surplus waters of Par, Auranga, Ambica and Purna River basins to take over part of Narmada Canal command (Miyagam branch) after providing enroute irrigation. It is proposed that water saved in Sardar Sarovar Project, as a result of this transfer, would be taken further northwards to benefit water scarce areas of north Gujarat and also westwards in Saurashtra and Kutch regions. The construction of seven reservoirs on Par-Tapi-Narmada River Link Project would affect land use/land cover, settlements and infrastructure facilities within and around reservoir area. Thus, the submergence impact analysis of all the seven reservoirs of this project have been carried out by using remote sensing and GIS techniques for planning and designing of the structures. Out of the seven reservoirs, the paper discusses submergence analysis of Kelwan Dam reservoir which is located in geologically complex region of the Dangs district. The study attempts to assess the present problems of submergence of land, forest, agriculture, settlements and infrastructure facilities by using GIS techniques for taking alternative remedial measures prior and during construction of the dams.
