SYSTEMS, METHODS, AND APPARATUS FOR PROVIDING INDOOR NAVIGATION USING MAGNETIC SENSORS
First Claim
1. An apparatus comprising:
- an absolute position sensor coupled to a case attached to a moveable object including;
a light detecting sensor which detects uniquely timed pulses of light emitted from a light emitting device in proximity to the moveable object; and
circuitry configured to determine an identity of the light emitting device in proximity to the moveable object based on the sensed uniquely timed pulses of light; and
a motion sensor coupled to the case including;
a first magnetic field sensor configured to detect a polarity of a magnet as the magnet passes in proximity to the first magnetic field sensor;
a code wheel having two or more magnets alternately oriented with north and south polarities facing toward the first magnetic sensor, the code wheel positioned to rotate in unison with a wheel of the moveable object; and
encoder circuitry configured to determine an amount of rotation of the wheel of the moveable object based on an output of the first magnetic field sensor.
1 Assignment
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Accused Products
Abstract
An indoor navigational system determines a location of a moveable object in an indoor area and displays this location to a user. The system includes an absolute position sensor coupled to a case attached to a moveable object including a motion sensor coupled to a case including a first magnetic field sensor configured to detect a polarity of a magnet as the magnet passes in proximity to the first magnetic field sensor, a code wheel having two or more magnets alternately oriented with north and south polarities facing toward the first magnetic sensor, the code wheel positioned to rotate in unison with a wheel of the moveable object, and encoder circuitry configured to determine an amount of rotation of the wheel of the moveable object based on an output of the first magnetic field sensor.
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Citations
20 Claims
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1. An apparatus comprising:
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an absolute position sensor coupled to a case attached to a moveable object including; a light detecting sensor which detects uniquely timed pulses of light emitted from a light emitting device in proximity to the moveable object; and circuitry configured to determine an identity of the light emitting device in proximity to the moveable object based on the sensed uniquely timed pulses of light; and a motion sensor coupled to the case including; a first magnetic field sensor configured to detect a polarity of a magnet as the magnet passes in proximity to the first magnetic field sensor; a code wheel having two or more magnets alternately oriented with north and south polarities facing toward the first magnetic sensor, the code wheel positioned to rotate in unison with a wheel of the moveable object; and encoder circuitry configured to determine an amount of rotation of the wheel of the moveable object based on an output of the first magnetic field sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus comprising:
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a motion sensor connected to a case attached to a moveable object including; a first magnetic field sensor configured to detect a polarity of a magnet as the magnet passes in proximity to the first magnetic field sensor; a second magnetic field sensor configured to detect a polarity of a magnet as the magnet passes in proximity to the second magnetic field sensor; and a code wheel having at least two magnets alternately oriented with north and south polarities facing toward the first and second magnetic field sensors, the code wheel positioned to rotate in unison with a wheel of the moveable object; wherein the locations of the first and second magnetic field sensors are located at positions within the case such that their alignment with the code wheel corresponds to a quadrature encoder output. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method of operating an indoor navigation system, the method comprising:
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detecting, in a light detecting sensor coupled to a moveable object, uniquely timed pulses of light emitted from a proximately located emitting device; and transmitting from the light detecting sensor an absolute positioning signal including an identifier corresponding to the uniquely timed pulses of light enabling an absolute position of the moveable object to be determined; determining a first movement of a wheel of the moveable object based on detected changes in polarity of magnets alternately orientated with north and south polarities by a first magnetic field sensor; determining a second movement of the wheel of the moveable object based on detected changes in polarity of the magnets by a second magnetic field sensor; determining an amount of movement and a direction of movement of the moveable object based on the first and second movements; and transmitting a dead-reckoning signal indicative of the determined amount of movement and the direction. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification