FMS Guide

Aerosoft – Digital Aviation
CRJ-700 CRJ-900
FMS Guide
Revision Info
VOL
6
1-1-26
23-Apr-2017
PREFLIGHT
POS INIT PAGE
The position initialization is a crucial step when programming the FMS. To fully understand the importance of
this step, explaining the basic principle of inertial navigation systems is necessary. Basically an inertial
navigation system determines the movements / variations in movement after it is initialized and operational.
As soon as the initialization sequence is completed the INS is able to detect movement of the aircraft along any
axis and compute the travelled distance. Nevertheless, the INS is somewhat stupid as it doesn’t know its
position on earth when it was initialized.
The POS INIT page now tells the INS where it is situated – so with computing the direction and distance of
movements from a starting point on the INS is able to compute and display the aircrafts position. The more
accurate the position compared to the aircrafts real position is the more accurate the aircrafts path is
computed. That’s why you find the aircraft stands position normally written on the positions sign (see picture
below).
Gate_POS_Lat_Lon.jpg