Mobile Terminal Direction Estimation Using Body Shadowing

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Solution Overview

Problem

Conventional mobile terminal devices, such as smartphones, face difficulties in estimating the direction of a beacon due to the lack of a directivity-switching antenna, leading to increased costs and decreased convenience in object location searches using radio communication techniques.

Innovation Solution

A mobile terminal device equipped with a receiving antenna that detects radio signal orientation using a geomagnetic sensor and a controller to estimate the arrival direction based on radio field intensity, allowing for the specification of a beacon's location without the need for a directional antenna.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a mobile terminal device uses a non-directional antenna to receive radio signals, then the device complexity and cost are reduced, but the ability to estimate the direction of the beacon is lost

Engineering Contradiction:

Improveantenna structureVSAvoiddirection estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces the user's body as an intermediary element that naturally creates signal shadowing effects. By detecting radio field intensity variations caused by the user's body blocking the signal from different directions, the system can estimate beacon direction without requiring complex directional antenna structures. The user's body acts as a passive mediator that provides directional information through its physical presence and signal-blocking properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a special detector with a directional antenna is used to search for object locations, then the direction estimation accuracy is improved, but the ease of operation and convenience decrease

Engineering Contradiction:

Improvedirection estimation accuracyVSAvoiduser convenience

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent enables the mobile terminal device to automatically perform direction estimation using the user's body as a natural signal occluder. The system continuously monitors radio field intensity variations as the user moves or changes posture, and automatically calculates the beacon direction without requiring manual antenna rotation or special user actions. This self-service approach maintains high direction estimation accuracy while preserving ease of operation.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent utilizes dynamic changes in the user's body position and movement to gather directional information. As the user naturally moves their body, the signal shadowing pattern changes, providing multiple measurement opportunities for direction estimation. This dynamic approach allows the system to continuously update direction estimates without requiring active user participation in the measurement process.

Inventive Principle:

Principle #15Dynamics

3Ease of manufacture

If a mobile terminal device uses a non-directional antenna, then the ease of manufacture is improved, but the ability to specify beacon location is reduced

Engineering Contradiction:

Improvedevice manufacturingVSAvoidlocation search capability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the mechanical directional antenna system with an electronic signal analysis approach. Instead of using physically rotating or steerable antennas to determine direction, the system uses a fixed non-directional antenna combined with software-based analysis of radio field intensity variations caused by user body shadowing. This substitution maintains location search reliability while dramatically simplifying the manufacturing requirements.

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

Enables efficient and cost-effective location searching of objects by determining the direction and distance of a beacon using a non-directional antenna, improving user convenience and reducing equipment costs.

Implementation Method 1

a beacon that emits radio waves is attached to an object and the radio waves emitted from the beacon are received, for example, by a mobile terminal device

Methodology Applied

Scientific EffectRadio wave propagation: Electromagnetic Induction

Implementation Method 2

a sensor that detects an orientation of the mobile terminal device every time the radio signal is received by the receiving antenna

Methodology Applied

Scientific EffectGeomagnetic field sensing: Magnetic Field

Data Source

PatentUS9949082B2Mobile terminal device, location search method, and computer-readable recording medium

Publication Date: 2018.04.17 FUJITSU LTD

AI summary

A mobile terminal device includes: a receiving antenna that repeatedly receives a radio signal including predetermined identification information; a sensor that detects an orientation of the mobile terminal device every time the radio signal is received by the receiving antenna; and a controller that estimates an arrival direction of the radio signal based on radio field intensity of the radio signal which is received by the receiving antenna for each orientation when a plurality of different orientations are detected by the sensor.