US 5,854,843 AGranted

Virtual navigator, and inertial angular measurement system

AssigneeThe United States of America as represented by the Secretary of the Air Force

InventorsLawrence Jacknin, Mark A. Ericson

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Abstract

A position tracker uses an inertial angular measurement system, for measuring orientation and linear translation of a helmet on a human head for the synthesis by a host computer of virtual, directional audio over headphones sensors mounted on the helmut, includes a roll gyro sensor, a pitch gyro sensor, a yaw gyro sensor, an absolute roll tilt sensor coupled to a first universal signal conditioner, an absolute pitch tilt sensor coupled to a second universal signal conditioner, and an absolute yaw compensator. A data acquisition system is coupled between the sensors and the host computer for converting analog signals from the sensors into digital, angular orientation data. Each of the gyro sensors includes angular velocity detectors and solid state electronic devices connected to provide angular velocity signals at a given sample rate.

Claims6

Dependent claims

An audio system apparatus providing audio signals to a human operator, said audio signals perceived to originate from a particular fixed location in 3-dimensional aircraft enclosed space around the human operator and updated upon movement of said human operator comprising:

operator head to aircraft sensing means including a first solid state gyrochip angular rate sensor for sensing, with respect to said aircraft, head roll angular rate, a second solid state gyrochip angular rate sensor for sensing head pitch angular rate and a third solid state gyrochip angular rate sensor for sensing head azimuth angular rate, said first, second and third solid state gyrochips each containing a tuning fork element for transducing head angular rate information and providing inertial linear output voltage proportional to angular velocity, and first, second and third accelerometers for sensing, respectively, x, y and z coordinate system linear rate and providing linear output voltage proportional thereto;
compensation means connected to said operator head to aircraft sensing means to correct aircraft to head angular error of said sensing means including a first and second electrolytic tilt sensor for correcting error of said first and second solid state gyrochip angular rate sensors, respectively, and an emitter scanner azimuth compensator for correcting error of said third solid state gyrochip angular rate sensor, said emitter scanner system including:
means for transmitting a plane of light at a reference detector, and
means for notifying said audio synthesizer of angular position error
wherein said compensation means provides absolute external reference frame to correct for drift in relative angular rate measurements;
signal conditioners connected to said compensation means for providing AC power to said compensation means, and demodulating and amplifying output therefrom;
analog-to-digital converter means connected to said sensing means for converting analog linear output voltage signals therefrom into digital rate signals;
audio synthesizer means connected to said analog-to-digital converter means for integrating said digital rate signals into digital position signals and for encoding said digital position signals into an audio signal, said audio signal continually updated relative to the orientation of said human operator head to keep said audio signal stationary relative to said human operator;
and
means for providing said audio signal stereophonically to said human operator.

7 more elements

An audio system apparatus providing audio signals to a human operator, said audio signals perceived to originate from a particular fixed location around the human operator and updated upon movement of said human operator in a virtual reality environment comprising:

operator head to aircraft sensing means including a first solid state gyrochip angular rate sensor for sensing head roll angular rate, a second solid-state gyrochip angular rate sensor for sensing head pitch angular rate and a third solid state gyrochip angular rate sensor for sensing head azimuth angular rate;
said first, second and third solid-state gyrochips receiving power from two aircraft connected 12 V direct current converters and providing linear output voltage proportional to angular velocity, and first, second and third accelerometers for sensing, respectively, x, y and z coordinate system linear rate and providing linear output voltage proportional thereto;
first, second and third connectors connected to outputs of said first second and third solid-state gyrochip angular rate sensors;
a plurality of analog filters connected to said first second and third connectors for receiving and filtering noise from outputs of said first, second and third solid-state gyrochip angular rate sensors;
operational amplifiers connected to said first, second and third analog filters and said first, second and third accelerometers, respectively, for receiving and amplifying outputs therefrom;
8-channel analog-to-digital converter means for converting analog outputs from said operational amplifiers into digital form, said 8-channel analog-to-digital converter means including a data selector and a 4 MHZ clock for controlling rate of sampling outputs from said operational amplifiers;
a plurality of optical couplers connected to said 8-channel analog-to-digital converter means for receiving control signals from said 8-channel analog-to-digital converter means;
a fourth connector connected to said optical couplers;
audio synthesizer means connected to said fourth connector for integrating digital output of said 8-channel analog-to-digital converter means into digital position data and encoding said angular position data into an audio signal;
and
means for providing said audio signal to said human operator wherein said audio signal is perceived to originate from a particular location in 3D space around the listener, said audio signal updated upon movement of said human operator.

8 more elements

Dependencies are inferred from the claim text.