Is it possible to use Glonass and GPS in NAZA and A2
GLONASS is the Russian satellite navigation system that works similar to GPS.
See: http://en.wikipedia.org/wiki/GLONASS

Many smartphone such as Apple iPhone and iPad using GPS and Glonass at the same time to get more satellite and thus to improve navigation.Manufacturers of GPS devices say that adding GLONASS made more satellites available to them, meaning positions can be fixed more quickly and accurately, especially in built-up areas where the view to some GPS satellites is obscured by buildings.
The question is why DJI this can not make.

I think WKM and above does use Glonass (or something else) because they are often getting 15-18 satellites and there are never 15-18 GPS satellites in your view.

with the A2 15-19 Sat's, with the Naza we get only 7-9