Indoor Location Model Using Crowd-Sourced Inertial Navigation

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Solution Overview

Problem

Current indoor location determination methods for mobile devices rely on site surveys of wireless access points, which are time-consuming and become stale over time due to changes in access point locations, leading to inaccurate models.

Innovation Solution

A scalable method using crowd-sourced inertial navigation system (INS) signals from multiple client devices to create and maintain an accurate model of wireless access points by tracking user trajectories and scoring routes to identify frequently traveled areas and wireless signal signatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional site surveys are conducted to build indoor location databases, then initial model accuracy is improved, but the time and resources required increase significantly

Engineering Contradiction:
Improveindoor location model accuracyVSAvoidtime for site surveys
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system enables users to passively contribute location data through their mobile devices as they naturally move through indoor spaces. The crowd-sourced data collection mechanism eliminates the need for dedicated surveyors to manually visit each location, allowing the database to build and update itself through aggregated user trajectories and wireless signal measurements.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Mobile devices serve multiple functions: they act as both the user's personal device and as survey instruments for collecting location data. The same device used for communication and entertainment also captures wireless signal strengths, determines device positions through inertial sensors, and contributes to building the indoor location database, eliminating the need for specialized surveying equipment.

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

2Area of stationary object

If comprehensive site surveys are performed to cover tens of thousands of buildings, then database coverage is improved, but the complexity and cost of maintenance increase

Engineering Contradiction:
Improvedatabase coverage areaVSAvoidsurvey complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The system automatically collects and processes location data from numerous user devices across multiple buildings simultaneously. Each device independently contributes data as it moves through indoor spaces, and the server automatically aggregates, validates, and updates the database without requiring coordinated survey efforts across thousands of locations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The large-scale survey problem is divided into numerous small, independent data collection tasks performed by individual mobile devices. Each device independently maps its local environment and contributes trajectory data, which the server then integrates into the overall database. This segmentation allows parallel data collection across many buildings without increasing overall system complexity.

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If static databases are created through one-time surveys, then initial data consistency is improved, but the data becomes stale and inaccurate over time due to access point changes

Engineering Contradiction:
Improvedatabase consistencyVSAvoiddata accuracy over time
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The system transitions from static, one-time surveys to dynamic, continuous data collection. User devices continuously measure wireless signal strengths and update their position estimates as they move through indoor spaces, allowing the database to automatically adapt to changes in access point locations, additions, or removals without requiring re-surveying.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Instead of performing discrete, periodic re-surveys, the system maintains continuous data collection through ongoing user device usage. As long as users move through the covered areas, new data is continuously gathered and the database is incrementally updated, ensuring persistent accuracy without interruption to normal operations.

Inventive Principle:
Principle #20Continuity of useful action

4Measurement precision

If extensive site surveys are conducted to ensure accurate location modeling, then measurement precision is improved, but productivity of database creation decreases

Engineering Contradiction:
Improvelocation model accuracyVSAvoiddatabase creation speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The database creation process is transformed from an active surveying operation into a passive self-building process. Rather than surveyors actively collecting data point-by-point, the system passively accumulates location data from user devices as they naturally use their mobile phones for other purposes, dramatically accelerating database creation without sacrificing accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system merges the database creation function with normal mobile device usage. Users continue their regular activities with their devices while simultaneously contributing location data, combining two separate processes (daily device use and surveying) into one unified operation that achieves both productivity and accuracy goals.

Inventive Principle:
Principle #5Merging (Combining)

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 approach enables a passive and efficient site survey that maintains an up-to-date database of access points, improving accuracy and reducing the need for extensive site surveys, while ensuring user privacy through anonymization and aggregation of data.

Implementation Method 1

the inertial navigation signals may include one of: accelerometer data, gyroscope data, and compass data

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

the inertial navigation signals may include one of: accelerometer data, gyroscope data, and compass data

Methodology Applied
Scientific EffectGyroscope: Gyroscope

Implementation Method 3

the inertial navigation signals may include one of: accelerometer data, gyroscope data, and compass data

Methodology Applied
Scientific EffectCompass: Magnetic Field

Implementation Method 4

Current techniques to determine indoor locations of mobile devices are based on interior scans of wireless access points. The scans may be used to build a database that can model an indoor space by determining locations of the access points and their corresponding signal strengths at those locations

Methodology Applied
Scientific EffectWireless signal propagation: Electromagnetic Induction

Data Source

PatentEP2885609B1Crowd-sourcing indoor locations
Publication Date: 2021.04.21 GOOGLE LLC
  • EP2885609B1 patent drawingFigure 1
  • EP2885609B1 patent drawingFigure 2
  • EP2885609B1 patent drawingFigure 3

AI summary

Aspects of the present disclosure provide techniques for constructing a scalable model of an indoor space using crowd-sourced inertial navigation system (INS) signals from mobile devices. By tracking INS signals from a number of participating users, the user's trajectories can be estimated as they move their mobile devices indoors. The estimated trajectories can be scored against similar routes taken by other users. Routes with the highest scores are then laid out over a map of the indoor space to identify areas most often traveled to and from landmarks and distances between the landmarks.