Time Offset Synchronization for Indoor Mobile Device Localization

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Solution Overview

Problem

Indoor navigation and positioning technologies face challenges in achieving precise localization without dedicated time synchronization hardware, particularly in ensuring that fixed and moving nodes share a common time reference frame for accurate time of flight-based solutions.

Innovation Solution

A method and system for time-offset based synchronization, where the time offset of each device is mathematically solved to enable precise positioning using the time difference of flight (TDOF) method, allowing localization of a moving node without the need for dedicated time synchronization hardware and clock corrections, utilizing a server computing device to derive the TDOF offset from wireless signal transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If time of flight based solutions are used for localization, then positioning precision is improved, but the requirement for common time reference frame between fixed nodes and moving node increases system complexity

Engineering Contradiction:

Improvepositioning precisionVSAvoidtime synchronization hardware

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces dedicated time synchronization hardware with a mathematical software-based solution. The system uses wireless signal transmissions between fixed nodes and moving nodes, combined with mathematical algorithms to calculate time offsets, thereby achieving time synchronization without physical synchronization hardware.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces wireless signal transmissions as an intermediary medium to establish time relationships between nodes. By measuring the time of flight of these signals and using mathematical calculations, the system derives time offsets that enable precise localization without direct hardware synchronization between nodes.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If dedicated time synchronization hardware is deployed, then time reference frame alignment is improved, but hardware cost and system complexity increase

Engineering Contradiction:

Improvetime reference frame alignmentVSAvoiddedicated hardware

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent substitutes dedicated time synchronization hardware with software-based mathematical calculations. The system processes wireless signal transmission data and computes time offsets algorithmically, eliminating the need for specialized hardware while maintaining reliable time reference frame alignment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables nodes to independently determine their time offsets through mathematical calculations based on wireless signal exchanges with other nodes. Each node can self-calculate its time relationship to the reference frame without requiring external hardware synchronization assistance.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If clock corrections are implemented, then time synchronization accuracy is improved, but the requirement for centralized clock management increases operational complexity

Engineering Contradiction:

Improvetime synchronization accuracyVSAvoidclock management

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent enables each node to independently calculate its own time offset through mathematical processing of wireless signal data. Nodes autonomously determine their synchronization status without requiring centralized clock management or manual intervention, simplifying operational complexity while maintaining high accuracy.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system uses wireless signal transmissions as feedback mechanisms to continuously measure and calculate time offsets. The mathematical processing of signal arrival times provides ongoing feedback that enables dynamic time synchronization adjustment without centralized control.

Inventive Principle:

Principle #23Feedback

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 precise mobile device positioning with accuracies of less than a meter, eliminating the requirement for dedicated hardware and clock corrections, while allowing the moving node to operate in its own time frame independent of the fixed nodes.

Implementation Method 1

Time of flight based solutions may be applied generally only when fixed nodes and a moving node both share a common time reference frame

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Data Source

PatentUS10820170B1Time offset based synchronization in mobile device localization

Publication Date: 2020.10.27 MAPSTED CORP

AI summary

A method and system of time-offset based synchronization for mobile device indoor navigation and positioning. The method, executed in a processor of a server computing device, comprises receiving, at a set of fixed nodes, a wireless signal transmission from a moving node; deriving a time difference of flight (TDOF) offset amongst the set of fixed nodes and the moving node; and localizing the moving node at a given time based at least in part on the TDOF offset.