In the fighter development program I recently retired from Mode S ES (ADSB) was a late after thought but it was implemented. But there is no ADSB in? So the fighter aircraft gets no big traffic picture in the normal civilian traffic environment that we now consider standard and can only detect a RV or any civilian ADSB equipped aircraft if it's either visual, called out by ATC, or picked up on its radar. While the fighter does have a basic IFF interrogator when the ILS is selected it turns off the IFF interrogator and that function is replaced with a Marker Beacon receiver function. Yes Marker Beacon (I know what your thinking). There is no GPS approach function or WAAS that we would consider standard. Plane uses Software function com/NAV radios and requires years and millions of dollars to change.