Adaptive Motion Signal Analysis for Indoor Positioning

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Solution Overview

Problem

Current position tracking systems for mobile devices within indoor environments face challenges such as inaccuracy, high costs, and inability to differentiate between positions behind obstacles, especially when relying on motion signals from non-proprietary devices worn in unintended locations.

Innovation Solution

The system employs adaptive filtering technology to extract pure movement data from motion sensors, using sensor fusion and pattern recognition to attribute motion signals to specific analysis parameter sets, and continuously updates these parameters for accurate tracking, even in complex environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If satellite-based positioning systems are used, then positioning coverage is improved, but they become unusable inside buildings due to lack of satellite RF signal availability

Engineering Contradiction:
Improvepositioning coverage areaVSAvoidpositioning availability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent introduces intermediate positioning methods (WiFi positioning, cellular positioning, inertial navigation) that serve as mediators when satellite-based positioning is unavailable. These intermediate systems allow continuous positioning functionality inside buildings by transitioning from GPS to alternative positioning technologies when satellite signals are not available.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If RF signal strength measurements (GSM, WiFi, Bluetooth) are used for indoor positioning, then positioning inside buildings is enabled, but system cost and complexity increase significantly

Engineering Contradiction:
Improveindoor positioning availabilityVSAvoidpositioning system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes mobile devices multi-functional by enabling them to perform both communication functions and positioning functions using existing infrastructure (cellular towers, WiFi access points). The same RF signals used for communication are also utilized for positioning through signal strength measurements and time of arrival measurements, eliminating the need for dedicated positioning hardware.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent enables positioning systems to self-configure and self-optimize by automatically selecting the most appropriate positioning method (GPS, WiFi, cellular, inertial) based on environmental conditions and signal availability. The system autonomously adjusts its operation without requiring manual configuration or intervention.

Inventive Principle:
Principle #25Self-service

3Device complexity

If motion sensors are used for position tracking, then positioning works without external infrastructure, but position accuracy degrades over time and distance due to drift

Engineering Contradiction:
Improvepositioning system simplicityVSAvoidposition accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent merges multiple positioning methods (GPS positioning, WiFi positioning, cellular positioning, and inertial navigation) into a unified hybrid positioning system. Each method compensates for the weaknesses of others: GPS provides absolute position when available, WiFi and cellular provide intermediate positioning, and inertial sensors provide continuous short-term tracking. The fusion of these methods maintains both simplicity and accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback mechanisms where the system continuously monitors the performance and availability of different positioning methods, then adjusts its operation accordingly. When drift is detected in inertial navigation, the system seeks external reference points (WiFi access points, cellular towers) to correct the position estimate, creating a closed-loop system that maintains accuracy over time.

Inventive Principle:
Principle #23Feedback

4Measurement precision

If beacon-based positioning systems are used, then position differentiation in interior zones is improved, but positioning is limited to areas where beacon signals can be received

Engineering Contradiction:
Improveposition differentiation accuracyVSAvoidpositioning coverage area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent uses existing communication infrastructure (cellular towers, WiFi access points) as copies or substitutes for dedicated beacon systems. These existing structures serve dual purposes: communication and positioning. By measuring signal strength and time of arrival to these ubiquitous structures, the system achieves position differentiation without requiring separate beacon infrastructure, thereby expanding coverage area while maintaining precision.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3105546B1Position tracking for a bearer of mobile device
Publication Date: 2021.09.22 FRAUNHOFER PORTUGAL RES
  • EP3105546B1 patent drawingFigure 1A~1C
  • EP3105546B1 patent drawingFigure 2
  • EP3105546B1 patent drawingFigure 3

AI summary

Mostly, motion signals are inaccurate, especially if the mobile device is not a proprietary device, and one has to reckon that the bearer wears the mobile device somewhere else than where it is supposed to be worn in order to coincide with the laboratory conditions. However, the information conveyed by the motion signals is sufficient in order to discriminate and detect between different typical wearing/carrying conditions, and accordingly position tracking based on such motion signals may be rendered far more efficiently by, first of all, using the motion signals gained from the one or more motion sensors so as to attribute them to one of a plurality of analysis parameter sets so as to obtain a selected analysis parameter set and, second, analyzing the motion signals using the selected analysis parameter set so as to obtain a signal indicating a locomotion of the bearer.