Signal processing to extract a pedestrian's moving direction
First Claim
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1. A method of determining a moving direction of a user of a mobile device, the method comprising:
- measuring, by an accelerometer, a raw acceleration reading;
detecting, by a gyroscope, an orientation of the mobile device;
determining, by one or more processors in the mobile device based on the raw acceleration reading and the detected orientation, an acceleration signal associated with the mobile device, the acceleration signal having three dimensions including an x dimension extending generally along a North-South direction, a y dimension extending generally along an East-West direction; and
a z dimension extending generally along a direction of Earth'"'"'s gravity;
determining, by the one or more processors in the mobile device, a step frequency of the user'"'"'s footsteps based on the z dimension of the acceleration signal, wherein the z dimension of the acceleration signal indicates whether the user is raising or lowering a foot;
fitting, by a moving direction estimation unit including one or more processors in the mobile device, the acceleration signal to a model including a sinusoidal function of time based on at least the step frequency, the model representing a vibration motion of the mobile device;
determining, by the moving direction estimation unit, the moving direction of the user based on the model, wherein determining the moving direction comprises;
filtering noise;
projecting modeled accelerations along x and y axes; and
computing modeled acceleration in the moving direction as a combination of the projected modeled accelerations along the x and y axes; and
providing for display on a screen the moving direction of the user in real time for independently guiding the user toward a target position.
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Abstract
Disclosed here are methods and systems that relate to determining a moving direction of a mobile device user. The methods and systems relate to using an inertial navigation system such as an accelerometer and gyroscope to aid in the determination of the moving direction of the user. The methods and systems may receive an acceleration reading associated with the mobile device, and determine a step frequency of the user based on the acceleration reading. The methods and systems may determine a theoretical model to fit the acceleration reading, and may determine the moving direction of the user based on the theoretical model.
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Citations
13 Claims
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1. A method of determining a moving direction of a user of a mobile device, the method comprising:
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measuring, by an accelerometer, a raw acceleration reading; detecting, by a gyroscope, an orientation of the mobile device; determining, by one or more processors in the mobile device based on the raw acceleration reading and the detected orientation, an acceleration signal associated with the mobile device, the acceleration signal having three dimensions including an x dimension extending generally along a North-South direction, a y dimension extending generally along an East-West direction; and
a z dimension extending generally along a direction of Earth'"'"'s gravity;determining, by the one or more processors in the mobile device, a step frequency of the user'"'"'s footsteps based on the z dimension of the acceleration signal, wherein the z dimension of the acceleration signal indicates whether the user is raising or lowering a foot; fitting, by a moving direction estimation unit including one or more processors in the mobile device, the acceleration signal to a model including a sinusoidal function of time based on at least the step frequency, the model representing a vibration motion of the mobile device; determining, by the moving direction estimation unit, the moving direction of the user based on the model, wherein determining the moving direction comprises; filtering noise; projecting modeled accelerations along x and y axes; and computing modeled acceleration in the moving direction as a combination of the projected modeled accelerations along the x and y axes; and providing for display on a screen the moving direction of the user in real time for independently guiding the user toward a target position. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for determining a moving direction of a user of a mobile device, the apparatus comprising:
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an accelerometer configured to measure a raw acceleration reading; a gyroscope configured to detect an orientation of the mobile device; an acceleration determination unit, including one or more processors in the mobile device, configured to determine an acceleration signal associated with the mobile device based on the raw acceleration reading and the detected orientation, the acceleration signal having three dimensions including an x dimension extending generally along a North-South direction, a y dimension extending generally along an East-West direction; and
a z dimension extending generally along a direction of Earth'"'"'s gravity;a step frequency determination unit, including one or more processors, configured to determine a step frequency of the user'"'"'s footsteps based on the z dimension of the acceleration signal; a moving direction estimation unit, including one or more processors, configured to; fit the acceleration signal to a model including a sinusoidal function of time based on at least the step frequency, the model representing a vibration motion of the mobile device; determine the moving direction of the user based on the model, wherein determining the moving direction comprises; filtering noise; projecting modeled accelerations along x and y axes; and computing modeled acceleration in the moving direction as a combination of the projected modeled accelerations along the x and y axes; and a display in communication with the one or more processors of the moving direction estimation unit, the display configured to depict the moving direction of the user in real time for independently guiding the user toward a target position. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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Specification