Integrated inertial VMS navigation with inertial odometer correction

This invention relates to the use of inertial navigation systems (INS) on vehicle such as trucks and tanks, in particular integrating INS with a mechanical odometer of Vehicle Motion Sensor (VMS) on the vehicle. A system for determining accurate inertial navigation data of a vehicle while moving must compensate for the orientation differences between an upper body and a lower body of the vehicle. These orientation differences are used to increase the accuracy of the aided inertial navigation solution. An odometer on the lower body is used to reduced errors in the inertial data arising from movement between the upper and lower bodies and errors in the odometer associated with vehicle pitch are reduced by sensing pitch changes with the inertial navigation data.