A.Goonhilly, UKB.Yamaguchi, JapanC.Perth, AustraliaD.So……

单项选择题Each NCS woks as a type of（）, assisting controlling and monitoring telex and telephone network as quickly as possible.

A.switch operator
B.communication gateway
C.national operator
D.on-scene commande

单项选择题The position of the AOR-W satellite in the INMARSAT system is（）above the equator.

A.64.5E
B.178E
C.15.5W
D.54W

单项选择题Geostationary satellite are artificial satellite which（）.

A.always move slowly
B.are in one place only
C.sometimes move and sometime don‟t
D.synchronize with the movement of the earth

单项选择题A radio link between a transmitting earth station and a receiving earth station through one satellite is named a（）.

A.Radio link
B.Space segment
C.Satellite link
D.upper link

单项选择题International Navtex service is（）.

A.a terrestrial MF system
B.a satellite communication system
C.a land HF radio system
D.a coastal VHF system