User Moving Direction Estimation Using Acceleration and Geomagnetic Sensors

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Solution Overview

Problem

Existing personal navigation systems using geomagnetic and acceleration sensors face challenges in accurately determining the moving direction of a user, especially when the sensor axis does not match the user's movement direction due to varying carrying positions or postures of the device.

Innovation Solution

A method and apparatus that utilize an acceleration sensor to calculate a reaction vector of force applied to the ground surface and an included angle between this vector and the geomagnetic sensor axis, allowing for determination of the user's moving direction regardless of the device's carrying position or posture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the geomagnetic sensor axis is assumed to match the user's moving direction, then the moving direction can be determined using the azimuth angle, but the accuracy deteriorates when the device carrying position or posture varies

Engineering Contradiction:

Improvemoving direction measurement accuracyVSAvoidadaptability to varying carrying positions and postures

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces an acceleration sensor as an intermediary to detect the device's orientation and carrying position. The acceleration sensor measures gravitational acceleration components to calculate the device's tilt angle and orientation relative to the user's body, which then serves as a mediator to correct the geomagnetic sensor's azimuth angle measurement and determine the actual moving direction accurately regardless of carrying position or posture.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical assumption that the sensor axis must physically align with the moving direction with a computational correction system. Instead of relying on physical alignment, the system uses acceleration sensor data to calculate orientation transformations and substitutes the mechanical alignment requirement with mathematical corrections to the geomagnetic sensor readings.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the axis of the geomagnetic sensor is assumed to match the moving direction, then the moving direction can be determined, but the measurement becomes unreliable when the device is carried in different positions or postures

Engineering Contradiction:

Improvemoving direction determination reliabilityVSAvoidmoving direction measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the acceleration sensor continuously monitors the device's orientation and carrying position, and this information is fed back to correct the geomagnetic sensor's azimuth angle measurements. The system iteratively adjusts the moving direction calculation based on real-time acceleration data, ensuring reliable and accurate measurements regardless of how the device is carried.

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate determination of the user's moving direction by converting acceleration data into a navigation frame and calculating the included angle, improving accuracy even when the sensor axis does not align with the user's movement.

Implementation Method 1

obtaining change information of acceleration according to motions of the user from an acceleration sensor

Methodology Applied

Scientific EffectGravitation: Gravitation

Implementation Method 2

calculating a reaction vector of force applied to a ground surface by the feet of the user based on the change information of acceleration

Methodology Applied

Scientific EffectReaction force: Reaction (physics)

Implementation Method 3

calculating an included angle between the moving direction of the user based on the reaction vector and an axis of a geomagnetic sensor that is included in the apparatus and detects change information of a magnetic field according to a position of the user

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentUS9151622B2Method and apparatus for estimating moving direction of user and computer-readable storage medium having recorded thereon the method

Publication Date: 2015.10.06 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of estimating a moving direction of a user of an apparatus is provided. The method includes obtaining change information of acceleration according to motions of the user from an acceleration sensor mounted in an apparatus for estimating the moving direction of the user, calculating a reaction vector of force applied to a ground surface by feet of the user based on the change information of the acceleration, calculating an included angle between the moving direction of the user based on the reaction vector and an axis of a geomagnetic sensor that is included in the apparatus and detects change information of a magnetic field according to a position of the user, and determining the moving direction of the user based on a moving direction measurement value of the geomagnetic sensor mounted in the apparatus and the included angle.