Yes, there is a GPS on the Boeings (prolly on the 'busses aswell)
But the primary navigation system is IRS, although that's a relative old technology compared to the GPS.

But as time goes by, the GPS system will eventually replace the IRS.

IRS= Inertial Reference System

Quote:


It is not modelled in FS2004..since it is a fairly advanced device (even though it's "old").  The IRS is actually 2 independent computers (IRS L, IRS R).

Before departure, i'ts very important to put the correct position coordinates into the IRS  AND in the Flight management computer (FMC) which uses both IRS and GPS positions for navigational references. The correct coordinates for resp. gates are printed on airport charts.

In the 737/747 (and for all newer Boeings) you'll find the IRS display on the overhead panel.


(IRS display on a 737 NG)

Hope this helps.

Tupolevs have to do it with Cessna-type GPS kits, NDB and RBSN(VHF-NDB), but mostly by visual refrence (that's where those glass noses are for). lots of workload...