Indoor Positioning via Relative Feature Spot Maps

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Solution Overview

Problem

Existing mobile inertial location tracking systems for indoor navigation suffer from accumulating errors due to sensor noise and require initial absolute position information, which can be absent if no seed landmarks are available, leading to inaccurate tracking.

Innovation Solution

A mobile device equipped with motion sensors and proximity sensors to establish relative feature spot maps based on movement directions and electromagnetic field characteristics, which are then matched to absolute feature spot maps to determine the device's absolute coordinates without needing an initial seed landmark.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If inertial tracking is used for indoor positioning, then tracking can be performed without external references, but accumulating errors occur due to sensor noise

Engineering Contradiction:

Improvetracking capability without external referencesVSAvoidpositioning accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system uses detected feature spots (WiFi access points, Bluetooth beacons, magnetic field characteristics) as feedback references to periodically correct and recalibrate the inertial tracking accumulated position, thereby eliminating positioning drift while maintaining continuous tracking capability

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces feature spots (electromagnetic field sources, magnetic anomalies, WiFi access points) as intermediary reference objects that mediate between the inertial tracking system and the absolute coordinate system, enabling error correction without requiring direct external reference systems

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If seed landmarks are used to initialize inertial tracking, then absolute position can be determined, but the system fails when no seed landmarks are available

Engineering Contradiction:

Improveabsolute position determinationVSAvoidcapability when no landmarks available

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system performs self-initialization by automatically detecting and utilizing any available feature spots (WiFi access points, Bluetooth beacons, magnetic field characteristics) in the environment to establish absolute position, eliminating the requirement for pre-configured seed landmarks

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent changes the initialization parameter from requiring specific seed landmarks to accepting any detectable feature spots with identifiable characteristics, thereby expanding the system's adaptability to environments without traditional landmarks

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If feature spots with absolute coordinates are used for recalibration, then positioning accuracy is maintained, but the system requires external reference infrastructure

Engineering Contradiction:

Improvepositioning accuracy through recalibrationVSAvoidrequirement for external reference infrastructure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses naturally occurring or existing electromagnetic field sources (WiFi access points, Bluetooth beacons, magnetic field anomalies) as intermediary reference objects, eliminating the need for dedicated external reference infrastructure while maintaining recalibration capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system leverages the mobile device's existing sensors (magnetometer, WiFi receiver, Bluetooth receiver) to autonomously detect and utilize feature spots in the environment, making the recalibration process self-service without requiring external reference system deployment

Inventive Principle:

Principle #25Self-service

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 indoor tracking by determining absolute coordinates using relative feature spot maps and electromagnetic field data, enhancing tracking accuracy and eliminating the need for external references or initial seed landmarks.

Implementation Method 1

one or more motion sensors being configured for detecting directions and/or distances of a movement of the mobile device

Methodology Applied

Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

one or more proximity sensors being configured for detecting characteristics of one or more electromagnetic fields

Methodology Applied

Scientific EffectElectromagnetic field detection: Magnetic Field

Data Source

PatentUS11467246B2Determining a position of a mobile device within buildings

Publication Date: 2022.10.11 FRAUNHOFER PORTUGAL RES

AI summary

A mobile device is configured for determining a position of the mobile device within buildings, the mobile device including: one or more motion sensors; one or more proximity sensors; a relative feature spot map establishing module; wherein the relative feature spot map establishing module is configured for transmitting the one or more relative feature spot maps to an absolute coordinates determining module configured for determining absolute coordinates of the mobile device; wherein the absolute coordinates determining module is configured for determining the absolute coordinates of the position of the mobile device by determining to which absolute feature spot map of the absolute feature spot maps the one or more relative feature spot map correspond.