Interferometric Location Sensing via Phase Difference Detection

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Solution Overview

Problem

Existing wireless communication systems face challenges in accurately locating mobile devices indoors and in urban environments due to the reliance on weak satellite signals and inaccurate cellular network triangulation methods.

Innovation Solution

The method involves detecting phase differences between radio signals received from multiple antennas of fixed transceivers to compute angles of departure or arrival, allowing for the determination of location coordinates of mobile transceivers without establishing an association, using a processor to process these signals and refer them to a map of fixed transceiver locations for precise positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If GPS satellite signals are used for location finding, then location coordinates can be obtained outdoors, but the method fails indoors and in crowded urban environments due to weak satellite signals

Engineering Contradiction:

Improvelocation finding reliabilityVSAvoidweak satellite signals

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces wireless communication infrastructure (access points and cellular base stations) as an intermediary system to enable location finding in environments where GPS satellite signals are blocked. Instead of directly receiving satellite signals, the mobile device uses locally available wireless infrastructure signals as a mediator to determine its position through angle-of-arrival measurements and triangulation methods.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If cellular network triangulation is used for location finding, then location can be determined using existing cellular infrastructure, but the accuracy and reliability are insufficient

Engineering Contradiction:

Improveuse of existing infrastructureVSAvoidlocation accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the location finding process into multiple independent measurement stages: first measuring the angle of arrival from multiple cellular base stations, then measuring angles from multiple access points, and finally combining these measurements through triangulation. This segmentation allows each measurement to be optimized independently, improving overall accuracy compared to traditional cellular triangulation that relies on signal strength alone.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional two-dimensional cellular triangulation based on signal strength to a three-dimensional approach by incorporating angle-of-arrival measurements from multiple antennas. This adds angular dimensionality to the location determination process, enabling more precise positioning by creating intersecting bearing lines that converge on the mobile device's location.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If angle of arrival measurements from multiple antennas are used, then location accuracy is improved, but the device complexity increases due to multiple antennas and processing requirements

Engineering Contradiction:

Improvelocation accuracyVSAvoidmultiple antennas and processing

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the wireless communication infrastructure serve multiple functions: it provides both communication services and location finding capabilities. The same access points and base stations used for data transmission are also used as reference points for angle-of-arrival measurements, eliminating the need for separate dedicated location finding hardware and reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The mobile device performs its own angle-of-arrival measurements and location calculations using its onboard processor and antenna array. The device autonomously processes the received signals from multiple base stations and access points to determine its position, without requiring external assistance from the network infrastructure or centralized processing, thereby reducing system complexity.

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

This approach enables accurate and reliable location finding of mobile devices within indoor and urban environments, independent of GPS, by leveraging the infrastructure of wireless communication access points and cellular base stations, enhancing navigation and asset tracking applications.

Implementation Method 1

detecting phase differences between radio signals received from multiple antennas of fixed transceivers to compute angles of departure or arrival

Methodology Applied

Scientific EffectPhase difference detection: Interference

Data Source

PatentUS11550024B2Interferometric location sensing

Publication Date: 2023.01.10 DEEYOOK LOCATION TECH LTD

AI summary

A method for location finding includes detecting a respective phase difference between the received radio signals that are associated with each of the multiple antennas of each of the fixed transceivers. One or more respective angles are computed between each of the fixed transceivers and the mobile transceiver based on the respective phase differences. Location coordinates of the mobile transceiver are found based on the angles and the transmit locations of the transmitters.