Ours just uses the ground based aids to calculate it's present position
We have Honeywell SPZ8000 Digital Integrated Flight Control Systems, depending on the source selected the Flight Guidance System will follow the instructions given by the crew, using a VOR as the source, the LNAV will track the selected course, using the FMS as the source, the LNAV will follow the inserted flight plan, or any direct to instructions, holding instructions, in fact it will even fly in circles around a given point at a distance of 1nm to 99.9 nms......
But considering that all of this falls under the title of Lateral Navigation, isnt that what it's supposed to do?
Mutt