The construction of a navigation system plays an important role in the development of national politics,economy and military affairs.Nowadays,the Beidou navigation system is facing a transition period from the regiona...The construction of a navigation system plays an important role in the development of national politics,economy and military affairs.Nowadays,the Beidou navigation system is facing a transition period from the regional navigation system to the global one.For the global constellation,the system performance will not be seriously degraded when one or two satellites are invalid,but it is out of case for the regional constellation,which usually has fewer satellites and less redundancy.This paper deals with this problem of hybrid constellations and analyzes the influence of the disabled satellites on the system.With hybrid constellations and simulation methods designed,the influence of invalid satellites on the navigation system is fully investigated.展开更多
To evaluate transmission rate of highly dynamic space networks,a new method for studying space network capacity is proposed in this paper. Using graph theory,network capacity is defined as the maximum amount of flows ...To evaluate transmission rate of highly dynamic space networks,a new method for studying space network capacity is proposed in this paper. Using graph theory,network capacity is defined as the maximum amount of flows ground stations can receive per unit time. Combined with a hybrid constellation model,network capacity is calculated and further analyzed for practical cases. Simulation results show that network capacity will increase to different extents as link capacity,minimum ground elevation constraint and satellite onboard processing capability change. Considering the efficiency and reliability of communication networks,how to scientifically design satellite networks is also discussed.展开更多
文摘The construction of a navigation system plays an important role in the development of national politics,economy and military affairs.Nowadays,the Beidou navigation system is facing a transition period from the regional navigation system to the global one.For the global constellation,the system performance will not be seriously degraded when one or two satellites are invalid,but it is out of case for the regional constellation,which usually has fewer satellites and less redundancy.This paper deals with this problem of hybrid constellations and analyzes the influence of the disabled satellites on the system.With hybrid constellations and simulation methods designed,the influence of invalid satellites on the navigation system is fully investigated.
基金Sponsored by the National Natural Science Foundation of China(Grant No.6137110061001093+6 种基金61401118)the Natural Science Foundation of Shandong Province(Grant No.ZR2014FP016)the Natural Scientific Research Innovation Foundation in Harbin Institute of Technology(Grant No.HIT.NSRIF.2011114HIT.NSRIF.2013136HIT.NSRIF.2016100)the Scientific Research Foundation of Harbin Institute of Technology at Weihai(Grant No.HIT(WH)201409HIT(WH)201410)
文摘To evaluate transmission rate of highly dynamic space networks,a new method for studying space network capacity is proposed in this paper. Using graph theory,network capacity is defined as the maximum amount of flows ground stations can receive per unit time. Combined with a hybrid constellation model,network capacity is calculated and further analyzed for practical cases. Simulation results show that network capacity will increase to different extents as link capacity,minimum ground elevation constraint and satellite onboard processing capability change. Considering the efficiency and reliability of communication networks,how to scientifically design satellite networks is also discussed.
