【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】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,...