Patent ID: 7421343
Filing Date: 2008-09-02
Classification: G01C

Abstract:
1. A system for reducing bias errors in an inertial sensor operating within an environment, the system comprising: an inertial sensor having an output; a vibration detector for sensing vibration changes within the environment proximate to the inertial sensor and operatively connected to the output of the inertial sensor, the vibration detector adapted for outputting a bias shift signal containing information of any vibration-induced bias shift in the inertial sensor; a Kalman filter for computing an estimate of the navigational error produced by the inertial sensor due to the vibration-induced bias shift, the Kalman filter having a first input, a second input, and an output, the first input of the Kalman filter directly connected to the output of the vibration detector, the output of the Kalman filter adapted for outputting a navigation correction based at least in part on actual measurement data from a comparator unit and from the bias shift signal outputted by the vibration detector; an error compensation unit having a first input, a second input, and an output, the first input of the error compensation unit directly connected to the output of the inertial sensor, the second input of the error compensation unit operatively connected to the output of the Kalman filter; and a strapdown navigator having a first input, a second input, and an output, the first input of the strapdown navigator operatively connected to the output of the error compensation unit, the second input of the strapdown navigator operatively connected to the output of the Kalman filter; wherein the comparator unit has a first input, a second input, and an output, the first input of the comparator unit operatively connected to the output of the strapdown navigator, the second input of the comparator unit operative to receive position data, and the output of the comparator unit operatively connected to the second input of the Kalman filter.