Antrix and Ascent is the same emulator, its just that Antrix is the OLD name.
So, if you use the latest version, or close to, the emulator you use is Ascent. If you use a very old version, (Around 400 updates ago..) then its still Antrix.
Just wanted to clear it out, as so many seem to call Ascent for Antrix. (Even tho Antrix sounds allot better...)