US 5,645,077 A · Inertial orientation tracker apparatus having automatic drift compensation for tracking human head and other similarly sized body

Abstract

A self contained sensor apparatus generates a signal that corresponds to at least two of the three orientational aspects of yaw, pitch and roll of a human-scale body, relative to an external reference frame. A sensor generates first sensor signals that correspond to rotational accelerations or rates of the body about certain body axes. The sensor may be mounted to the body. Coupled to the sensor is a signal processor for generating orientation signals relative to the external reference frame that correspond to the angular rate or acceleration signals. The first sensor signals are impervious to interference from electromagnetic, acoustic, optical and mechanical sources. The sensors may be rate sensors. An integrator may integrate the rate signal over time. A drift compensator is coupled to the rate sensors and the integrator. The drift compensator may include a gravitational tilt sensor or a magnetic field sensor or both. A verifier periodically measures the orientation of the body by a means different from the drift sensitive rate sensors. The verifier may take into account characteristic features of human motion, such as stillness periods. The drift compensator may be, in part, a Kalman filter, which may utilize statistical data about human head motion.

Claims44

Dependent claims

An apparatus to be attached to a body having a size between the sizes of a human finger and a human torso, said body having an orientation, relative to an external reference frame, said apparatus generating an orientation signal that corresponds to at least two degrees of freedom of said orientation of said body, said apparatus comprising:

a. a self contained sensor that generates first sensor signals that correspond to x.sup.th order integrals of rotational accelerations of said body about at least two axes of said body, x being selected from the group consisting of 0, 1 and 2 and said first sensor signals being impervious to any interference from electromagnetic, acoustic, optical and mechanical sources;
b. a mechanism for mounting said sensor to said body;
and
c. coupled to said sensor, a signal processor that generates an orientation signal that corresponds to said at least two degrees of freedom of said orientation of said body.

1 more element

An apparatus for simulating a virtual environment that is displayed to a user by an appropriate display device, said apparatus comprising:

a. a self contained orientation sensor to be attached to a body member of said user that has an orientation and a position relative to a reference frame, said sensor generating an orientation signal that:
i. corresponds to at least two degrees of freedom of said orientation of said body member;
and
ii. is impervious to interference from electromagnetic, acoustic, optical and mechanical sources;
b. a position sensor that generates a position signal that corresponds to said position of said body member;
c. a mechanism for mounting said position and orientation sensors to said body member;
d. a virtual environment means for generating virtual environment signals that define, in part, a virtual environment;
e. a display that displays said virtual environment signals to said user;
and
f. means for coupling said position sensor and said orientation sensor to said virtual environment means.

7 more elements

Dependencies are inferred from the claim text.

Inertial orientation tracker apparatus having automatic drift compensation for tracking human head and other similarly sized body

Life of this patent

Inertial orientation tracker apparatus having automatic drift compensation for tracking human head and other similarly sized body

Life of this patent

Abstract

Claims44