Changing inertial frame of reference, exactly.The Frame part of FSD comes from "Frame of Reference". It does not refer to the ships hull, or anything like that. FSD = A device (drive) that moves (shifts) your frame of reference.
I would assume that it is specifically the Inertial frame of reference that is being changed.
Frame of Reference = Система отсчёта
Inertial Frame of Reference = Инерциа́льная систе́ма отсчёта
John Roberts
As for suitable Russian words or phrases, online dictionary lead me to these suggestions too:
фрейм (very direct, but if you want to avoid 'Anglisms', then maybe not good
условия
система взглядов
Hope these help.