摘要：In December 2005 the first Galileo prototype satellite, GIOVE-A, was launched. Then, on April 26, 2008, a second satellite — GIOVE-B — was successfully put into orbit and soon began transmitting a variety of signals.
With two operational satellites in place, and having two receivers available, which can track both satellites’ signals at the same time (using omni-directional antennas), one can perform a Galileo-only double-difference calculation and analysis.
