Mobile Device RFID Direction Determination

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Solution Overview

Problem

Conventional RFID tracking systems and augmented reality systems face challenges such as high costs, complexity in setup, difficulty in scaling, and limitations in visual-based object detection, including occlusion and poor lighting, which hinder effective localization and recognition of objects from multiple perspectives.

Innovation Solution

A mobile device equipped with an RFID reader and motion sensors determines the direction and location of RFID tags using signal strength indicators, enabling radio-based wireless communication to overcome visual domain limitations and provide accurate object localization from any perspective without the need for visual recognition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple stationary RFID readers with high power antennas are used for triangulation, then localization accuracy is improved, but system cost and complexity increase

Engineering Contradiction:

Improvelocalization accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of using multiple stationary readers to triangulate the tag's position, the patent inverts the approach by using a single moving mobile device to track the tag. The mobile device carries the RFID reader and uses motion sensors to track its own movement, then determines direction to the tag based on signal strength variations as it moves, effectively reversing the traditional triangulation setup.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The mobile device performs its own localization tracking without requiring external infrastructure. By carrying the RFID reader and using its own motion sensor data, the mobile device independently determines the direction and location of RFID tags, eliminating the need for multiple stationary readers and complex triangulation systems.

Inventive Principle:

Principle #25Self-service

2Reliability

If visual-based AR systems are used for object detection, then object recognition is achieved, but the system fails under occlusion and poor lighting conditions

Engineering Contradiction:

Improveobject recognition reliabilityVSAvoidocclusion and lighting limitations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces visual-based optical detection with radio-based RFID detection. Instead of using cameras and visual processing that are sensitive to lighting and occlusion, the system uses RFID readers to detect tags via radio waves, which can penetrate obstacles and are unaffected by lighting conditions, thereby eliminating the harmful effects of occlusion and poor lighting.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If visual-based AR systems require line-of-sight for object detection, then accurate positioning is achieved, but objects cannot be detected from all perspectives

Engineering Contradiction:

Improveobject positioning accuracyVSAvoiddetection perspective flexibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces line-of-sight visual detection with omnidirectional radio-based RFID detection. RFID tags can be detected from any direction without requiring visual line-of-sight, allowing the mobile device to locate tags even when positioned behind or around objects, thereby providing full 360-degree detection capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This solution allows for cost-effective, scalable, and reliable object localization and tracking, overcoming visual-based challenges like occlusion and lighting issues, and enabling accurate object detection from any angle, even behind the user, by using radio-based wireless tags.

Implementation Method 1

Wireless tags used for wireless radio-signaling, such as radio frequency identification (RFID) tags

Methodology Applied

Scientific EffectRadio frequency identification (RFID): Electromagnetic Induction

Implementation Method 2

motion sensors, such as in an inertial measurement unit (IMU), to sense motion of the mobile device as a user moves and changes orientations of the device

Methodology Applied

Scientific EffectMotion sensing: Accelerometer

Data Source

PatentUS20190058969A1Direction determination of a wireless tag

Publication Date: 2019.02.21 MOTOROLA MOBILITY LLC

AI summary

In aspects of direction determination of a wireless tag, a mobile device can receive wireless signal replies that include signal strength indicators from a wireless tag in response to wireless communications from the mobile device to the wireless tag. The mobile device can include a tracking module that is implemented to track movement of the mobile device based on motion sensor inputs, and identify a location of the mobile device based on the movement of the mobile device. The tracking module is also implemented to determine a direction toward the wireless tag relative to the location of the mobile device based on the signal strength indicators in the wireless signal replies from the wireless tag.