Dynamic attitude measurement method and apparatus
A method and system senses the attitude of an accelerating object by measuring acceleration with accelerometers in three orthogonal axes and measuring angular rate with angular rate sensors disposed about each such axis to compute attitude of the object accurately relative to a vertical axis. A processor updates a quaternion representation of attitude based upon the angular rate of the object, and a corrective rate signal is determined from level frame acceleration as a reference for a Kalman filter in calculating the attitude of the object. When velocity or airspeed is available from an external source, an aiding algorithm is employed to provide accurate attitude representations throughout all flight regimes.
1. A system for correcting a predicted attitude of an accelerating body, comprising:
a processor for receiving external aiding data and for calculating a centripetal acceleration correction in response to the external aiding data; and,
an adaptive filter, coupled to the processor, for applying the centripetal acceleration correction to a tangential acceleration vector and correcting the predicted attitude of the accelerating body in response to the tangential acceleration vector.
2. The system for correcting the predicted attitude of claim 1 , wherein the external aiding data is a yaw rate measurement.
3. The system for correcting the predicted attitude of claim 1 , wherein the external aiding data is an airspeed measurement.
4. The system for correcting the predicted attitude of claim 1 wherein the adaptive filter is a Kalman filter.