The invention relates to a device, system, and method for providing a
multi-mode navigation device. In a first mode of operation, the
navigation device provides position information based on a radio
frequency navigation signals. If radio signals become unavailable, the
navigation device enters a second mode of operation. In the second mode
of operation the navigation device stores the most recent elevation and
associates it with a reference elevation, the reference elevation is
associated with an entry floor. The difference between a current
elevation and the reference elevation is determined and this difference
is divided by a floor height to obtain a floor number. The navigation
device provides the floor number while reliable global position
information is unavailable.