Patent ID: 8886366
Filing Date: 2014-11-11
Classification: G01C,G06F

Abstract:
1. Device to estimate the state of a moving vehicle, composed of an inertial measurement unit (IMU), measuring the angular velocities and the accelerations of said vehicle, by a camera (CAM) and by a device (PROC) for the processing of the terrain photographic images taken at successive instants, identifying a set of characteristic points of the terrain, which are tracked on the different images, and by a navigation filter (NF) which using a suitable algorithm calculates the state of the vehicle in terms of velocity, position, attitude and angular velocity, in a reference frame fixed with respect to the ground, characterized in that: the navigation filter, in order to get a unit vector (U), indicating the direction of the displacement of the vehicle between two time instants (T1) and (T2), performs the following two computing steps: to obtain the ratio, (RHO), between the lengths of the displacements of the vehicle, respectively in the timeframe from (TA) to (TM) and from (TM) to (TB), where (TA), (TM) and (TB) are three successive time instants, the navigation filter performs the following computations: to calculate the length of the displacement of the vehicle between two time instants, the navigation filter processes the said unit vectors (U), the said ratio (RHO), and the measurements of the inertial measurement unit, conveniently treated, together with the value of the gravity acceleration vector or the value of the norm of such vector.