【单选题】Cospas-Sarsat consists of ( ) satellites in polar orbit and a network of earth stations which provide distress alert and location information to appropr:iate rescue authorities, any- where in the w...
【单选题】听力原文: What is GPS? Its full name is the Global Positioning System and a satellite-based navigation system. Generally speaking, it is made up of a network of 24 satellites placed into orbit by the U. S...
【单选题】The Space Segment, consists of _______ operational satellites in six circular orbits 20,200 km above the earth at an inclination angle of 55 degrees with a 12-hour period.
【简答题】英译汉: Global Positioning System is a space-based radio-navigation system, consisting of 24 satellites and ground support. GPS provides users with accurate information about their position and velocity,...
【简答题】Few would deny the power and influence of television in today's world. In NorthAmerica, TV programs are on the air 18 to 24 hours a day, 365 days of the year.With the arrival of cable television and s...