The "A-train" is a constellation of six Franco-American Earth observation satellites in sun-synchronous orbit at an altitude of 690 kilometers above the Earth. They are spaced a few minutes apart from each other so their collective observations may be used to build high-definition three-dimensional images of the Earth's atmosphere and surface.
The train consists of the satellites:
AF to conduct satellite constellation simulations. (Air Force needs contractors to design simulation system for a Global Positioning System) (Defense Procurements)
Jan 13, 1993; * AF TO CONDUCT SATELLITE CONSTELLATION SIMULATIONS. Eglin AFB is preparing to solicit firms having the capability to design,...