Greetings
On the Thales/Smith FMS position is a computed position, elaborated by the FMS, using Hybrid GPS/IRS position provided by the FG.
They use a Kalman filter, to cater for the drift and maintain a high accuracy.
SO you end up with :
IRS/GPS hybrid
GPS
and FMS position
Triple mix is more a technology used by HWL, they did want to use KAlman filtering saying that it was not proven, but today they use it in their latest ADIRU (only idiots dont change their mind) they are using the barycenter and the FMS is computed using a blending of that value and GPS or RADNAV...
I hope you are not more confuse now.
