What are your thoughts? Is there a good reason why TSO'd gps' allow the navaid ident to be recieved even though you're tracking via GPS CDI (the position of the navaid) rather than the navaid itself?
The GPS receiver has nothing to do this, as it just sits there providing a signal that then is enunciated elsewhere.
Rather, it is the signal priority switching of the particular avionics installation the comes into the picture.
For example, long before GPS was available to civil aircraft users, what normally was used was triple INS, supplied to an FMS unit(s)
The Lockheed TriStar was the first to have this equipment (circa 1976 or thereabouts), and of course the area nav system from the FMS (RNAV) was normally used for enroute (and sometimes, terminal) navigation.
However, when an ILS approach was to be used, switching was done automatically...IE: if the pilot failed to switch manually from RNAV data to ILS nav data, when the ILS frequency was tuned and identified, the nav switching was done automatically on the respective display.
Fail/operational, a TriStar exclusive, at the time.