A medium earth orbit (MEO) tracking and data relay satellite system (TDRSS) constellation scheme for China is proposed. This system consists of MEO satellite constellation, inter-satellite links (ISLs) and terre...A medium earth orbit (MEO) tracking and data relay satellite system (TDRSS) constellation scheme for China is proposed. This system consists of MEO satellite constellation, inter-satellite links (ISLs) and terrestrial gateway station, which can provide continuous bidirectional data transmission links between low altitude spacecrafls and the terrestrial gateway station in China. Theoretical analysis and simulation results indicate that the proposed constellation can cover the global low altitude space sphere and earth surface of China continuously, and has a preferable practical perspective.展开更多
The satellite constellation classes, which are suitable for the medium earth orbit tracking and data relay satellite system (MEO-TDRSS) of China, are investigated. On the basis of the functionality and the traffic d...The satellite constellation classes, which are suitable for the medium earth orbit tracking and data relay satellite system (MEO-TDRSS) of China, are investigated. On the basis of the functionality and the traffic distribution characteristic of MEO-TDRSS, the coverage performance and inter-satellite link properties of four different constellation schemes are compared by simulations. Simulation results indicate that the rosette and common-track constellations, whose satellites are distributed on the celestial sphere more uniformly, are appropriate for the implementation of MEO-TDRSS of China.展开更多
A hybrid switching node structure with light and microwave links is proposed, which is applicable to the future data relay satellite systems, aiming at the development trend of coexistence of light- link and microwave...A hybrid switching node structure with light and microwave links is proposed, which is applicable to the future data relay satellite systems, aiming at the development trend of coexistence of light- link and microwave-link in the future. An experimental system for the light and microwave hybrid switching node based on wavelength selective optical switches (WSS) and optical transceiver modules, is established. It is shown by our experiment that this hybrid switching node can realize the dynamic bandwidth allocation and wavelength routing while the bit error rate of light link is less than 10?12, which provides a method for solving the hybrid switching problem of light-link and microwave-link on the future data relay satellite systems.展开更多
Nonhydrostatic mesoscale WRF and its 3D-Var system are used to study a dense fog event occurring in 13-14 January 2006. Three different observation data sets including GTS (Global Telecommunication System), AMDAR (...Nonhydrostatic mesoscale WRF and its 3D-Var system are used to study a dense fog event occurring in 13-14 January 2006. Three different observation data sets including GTS (Global Telecommunication System), AMDAR (Aircraft Meteorological Data Relay) data, and 9210 data are assimilated into the initial analysis fields in experiments. Experiments with three different assimilation time intervals (1, 3, and 6 h) are also carried out. Three experiments with different data sets have all modified the temperature and humidity field of initial fields, and therefore show an obvious positive effect on fog simulation. Further study indicates that the humidity and stability of boundary layer are improved obviously in assimilation experiments, although different data sets make different contribution to the analysis fields. The multi-time assimilation cycle experiments show that the analysis increment in experiment with l-h interval is more realistic than that with 3- and 6-h intervals.展开更多
基金National Natural Science Foundation of China (No. 60372013)
文摘A medium earth orbit (MEO) tracking and data relay satellite system (TDRSS) constellation scheme for China is proposed. This system consists of MEO satellite constellation, inter-satellite links (ISLs) and terrestrial gateway station, which can provide continuous bidirectional data transmission links between low altitude spacecrafls and the terrestrial gateway station in China. Theoretical analysis and simulation results indicate that the proposed constellation can cover the global low altitude space sphere and earth surface of China continuously, and has a preferable practical perspective.
基金the National Natural Science Foundation of China (60372013)
文摘The satellite constellation classes, which are suitable for the medium earth orbit tracking and data relay satellite system (MEO-TDRSS) of China, are investigated. On the basis of the functionality and the traffic distribution characteristic of MEO-TDRSS, the coverage performance and inter-satellite link properties of four different constellation schemes are compared by simulations. Simulation results indicate that the rosette and common-track constellations, whose satellites are distributed on the celestial sphere more uniformly, are appropriate for the implementation of MEO-TDRSS of China.
文摘A hybrid switching node structure with light and microwave links is proposed, which is applicable to the future data relay satellite systems, aiming at the development trend of coexistence of light- link and microwave-link in the future. An experimental system for the light and microwave hybrid switching node based on wavelength selective optical switches (WSS) and optical transceiver modules, is established. It is shown by our experiment that this hybrid switching node can realize the dynamic bandwidth allocation and wavelength routing while the bit error rate of light link is less than 10?12, which provides a method for solving the hybrid switching problem of light-link and microwave-link on the future data relay satellite systems.
基金Supported by the Ministry of Science and Technology of PRC under Contracts 2006BAC02B01National Natural Science Foundation of China under Grand Nos.40675022 and 60572184.
文摘Nonhydrostatic mesoscale WRF and its 3D-Var system are used to study a dense fog event occurring in 13-14 January 2006. Three different observation data sets including GTS (Global Telecommunication System), AMDAR (Aircraft Meteorological Data Relay) data, and 9210 data are assimilated into the initial analysis fields in experiments. Experiments with three different assimilation time intervals (1, 3, and 6 h) are also carried out. Three experiments with different data sets have all modified the temperature and humidity field of initial fields, and therefore show an obvious positive effect on fog simulation. Further study indicates that the humidity and stability of boundary layer are improved obviously in assimilation experiments, although different data sets make different contribution to the analysis fields. The multi-time assimilation cycle experiments show that the analysis increment in experiment with l-h interval is more realistic than that with 3- and 6-h intervals.