The answer is not really what you think here. GPS signals have a series of different transmitters. On each satellite, there are four for the military, two for civilian use, and two that work satellite to satellite. The sat to sat transmission help create the position that is transmitted to the ground radios. Adding a new position awareness for accuracy wouldn't be hard.
About the article, I'm glad to have GLONASS come out on consumer devices. I use a GPS/GLONASS hybrid receiver for land survey and construction lay out. We usually get about 12 GPS and 3 GLONASS on any given site, and those few extra raise our accuracy from 0.1 of a foot to .04 of a foot.