The early jets flew from navaid to navaid, and if the flew on an "selfmade" track they had to plot their position! Here in Europe, at least in Austria and Germany, you still have to learn plotting when you take your ATPL. On long range flights they had an IRS.
Today we don´t have an IRS but an INS!
Mainly there is the FMS (flight management system) and this gets it´s information from:
So if you have any questions about something else here, just ask me! If I would explain here the whole navigation stuff I would still sit around in a few days!!
yes i can handle that alone. - - -famous last words