Systems, methods, and apparatus for providing indoor navigation using magnetic sensors
First Claim
1. An apparatus comprising:
- a case including a (i) a first compartment configured to connect to a wheel hub of a wheel of a moveable object, and (ii) a second compartment protruding from the first compartment;
an absolute position sensor located within the second compartment and 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 located within the first compartment and 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 the 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,wherein the protrusion of the second compartment from the first compartment enables the light detecting sensor to detect the uniquely timed pulses of light.
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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.
66 Citations
23 Claims
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1. An apparatus comprising:
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a case including a (i) a first compartment configured to connect to a wheel hub of a wheel of a moveable object, and (ii) a second compartment protruding from the first compartment; an absolute position sensor located within the second compartment and 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 located within the first compartment and 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 the 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, wherein the protrusion of the second compartment from the first compartment enables the light detecting sensor to detect the uniquely timed pulses of light. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 14)
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12. An apparatus comprising:
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a case including a (i) a first compartment configured to connect to a wheel hub of a wheel of a moveable object, and (ii) a second compartment extending from the first compartment; a motion sensor located within the first compartment of the case and 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 the wheel of the moveable object; and a light detecting sensor located within the second compartment of the case, wherein the locations of the first and second magnetic field sensors are located at positions within the first compartment of the case such that their alignment with the code wheel corresponds to a quadrature encoder output, wherein the motion sensor is configured to cause the light detecting sensor to be operational after detecting that a number of magnetic polarity transitions sensed by at least one of the first magnetic field sensor and the second magnetic field sensor is greater than a threshold during a predetermined period of time, and wherein the extension of the second compartment from the first compartment enables the light detecting sensor to detect at least one pulse of light. - View Dependent Claims (13, 15, 16, 17)
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18. A method of operating an indoor navigation system, the method comprising:
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detecting, in a light detecting sensor located within a first compartment of a case connected to a moveable object, uniquely timed pulses of light emitted from a proximately located emitting device; 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, via a processor, 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 located within a second compartment of the case, the second compartment connected to a wheel hub of the wheel of the movable object; determining, via the processor, 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, via the processor, an amount of movement and a direction of movement of the moveable object based on the first and second movements; and transmitting, via the processor, a dead-reckoning signal indicative of the determined amount of movement and the direction, wherein the first compartment extends laterally from the second compartment to enable the light detecting sensor to detect the uniquely timed pulses of light. - View Dependent Claims (19, 20, 21, 22, 23)
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Specification