Patent ID: 7957899

Claim:
A method for determining attitude, position, and velocity of a mobile device from knowledge of a direction of earth's magnetic field in an absolute reference frame, signals supplied to processing means by gyroscopic measuring means in three axes, accelerometric measuring means in three axes, and magnetic measuring means in three axes, each of the measuring means being located on-board the mobile device and according to three three-dimensional reference frames connected to a mobile device reference frame O d X d Y d Z d , the method comprising: a first step in which an attitude of the mobile device is calculated by the processing means at time K−1 from: signals coming from the gyroscopic measuring means at time k; signals coming from the accelerometric measuring means at time k+1; a position and a velocity of the mobile device in the absolute reference frame at at time k; and signals supplied by the magnetic measuring means representing a projection of the earth's magnetic field in a three-dimensional magnetic reference frame linked to the mobile device, a second step in which the position and the velocity of the mobile device in an absolute frame point at time k+1 are calculated from: the attitude calculated in the first step; the signals coming from the accelerometric measuring means at time k+1; the signals coming from the gyroscopic measuring means at time k; the position and the velocity of the mobile device in the absolute reference frame at time k; and the signals supplied by the magnetic measuring means representing the projection of the earth's magnetic field in the three-dimensional magnetic reference frame.