Mobile Proximity Positioning Using RSSI Graph Fingerprints

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing proximity determination methods for mobile devices, such as those using Bluetooth Low Energy (BLE), are labor-intensive and require frequent recalibration due to changes in the radio environment, leading to potential loss of accuracy.

Innovation Solution

A method and system that uses a two-dimensional graph based on beacon measurements and device measurements to determine the most probable position of a mobile device relative to proximity determiners, utilizing a probability indicator to optimize proximity determination without relying on physical maps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fingerprinting-based positioning is used to improve positioning precision, then measurement precision is improved, but device complexity and ease of manufacture worsen due to labor-intensive setup and calibration requirements

Engineering Contradiction:
Improvepositioning precisionVSAvoidsetup and calibration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-calibration by automatically creating and updating fingerprints based on RSSI measurements from multiple devices without requiring manual intervention. The calibration process is automated through the server that collects measurements and generates fingerprints dynamically, eliminating the need for labor-intensive manual setup and recalibration.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary calibration actions by pre-establishing fingerprints during initial device connections and continuously updating them in the background. This preliminary action ensures that positioning can proceed immediately without requiring manual calibration at the time of use, and the system proactively maintains accuracy through automated updates.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If frequent recalibration is performed to maintain positioning accuracy, then measurement precision is improved, but loss of time and productivity worsen due to labor-intensive re-calibration requirements

Engineering Contradiction:
Improvepositioning accuracyVSAvoidrecalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system automatically performs recalibration without human intervention by collecting RSSI measurements from active devices and updating fingerprints in real-time. This self-service approach eliminates the time loss associated with manual recalibration while maintaining positioning accuracy through continuous background updates.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The calibration process continues uninterrupted in the background as devices naturally move through the environment and provide RSSI measurements. Instead of stopping operations for recalibration, the system continuously updates fingerprints using ongoing device activity, ensuring positioning accuracy without interrupting productivity.

Inventive Principle:
Principle #20Continuity of useful action

3Ease of operation

If RSSI threshold comparison is used to simplify proximity determination, then ease of operation is improved, but measurement precision worsens due to great variation in RSSI measurements

Engineering Contradiction:
Improveproximity determination simplicityVSAvoidproximity determination accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system uses feedback from multiple RSSI measurements from different devices to continuously refine fingerprints and improve proximity determination accuracy. By collecting and analyzing measurements from multiple sources, the system adapts to RSSI variations and maintains precise proximity detection while keeping the operation simple through automated processing.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system combines multiple RSSI measurements from different proximity determiners and devices to create a more robust proximity determination. By merging multiple data points into composite fingerprints, the system compensates for individual measurement variations and achieves accurate proximity detection while maintaining operational simplicity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4127762B1Enabling determination of proximity based on detectable proximity determiners
Publication Date: 2025.11.26 ASSA ABLOY AB
  • EP4127762B1 patent drawingFigure 1~2
  • EP4127762B1 patent drawingFigure 3~4
  • EP4127762B1 patent drawingFigure 5~7

AI summary

It is provided a method for enabling determination of proximity of a mobile device (2a, 2b) to a selected proximity determiner (3a). The method comprises the steps of: determining a base set of proximity determiners (3b-e) whereby an enlarged set of proximity determiners is defined as the selected proximity determiner and the base set of proximity determiners; receiving beacon measurements of signal strength of other proximity determiners in the enlarged set of proximity determiners; generating a two-dimensional graph based on the beacon measurements; receiving respective device measurements indicating signal strength of a signal from the mobile device at each proximity determiner in the enlarged set of proximity determiners; finding an optimum in a space defined by the two- dimensional graph; and determining the most probable position of the mobile device in the graph based on the optimum.