Vehicle Positioning Using Acoustic Reflection and Two Receivers

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Solution Overview

Problem

Current positioning systems require three or four receivers to accurately determine a user device's position in three dimensions, which increases cost and complexity, and may not function accurately in environments with limited GPS reception, such as parking garages or dense cities.

Innovation Solution

A method using two receivers in the vehicle that employs time synchronization and reflected signals, specifically acoustic signals, to determine the user device's position in three dimensions, reducing system requirements and cost while maintaining accuracy, even if the reflected signal is not from the ground plane.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If three or four receivers are used to determine position in three dimensions, then positioning accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidnumber of receivers
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention introduces a ground plane as an intermediary reflective surface to create virtual image receivers. The ground plane reflects signals from the actual receivers to create additional signal paths, effectively providing the equivalent of having more receivers without physically adding them. This allows 3D positioning with only two physical receivers by utilizing the reflected signals from the ground plane to determine the vertical position component.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If GPS is used for positioning, then system simplicity is maintained, but positioning accuracy is insufficient and GPS may not function in certain environments

Engineering Contradiction:
Improvesystem simplicityVSAvoidpositioning accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The invention segments the positioning function into two parts: using GPS for coarse 2D horizontal positioning when available, and using the acoustic signal reflection method for precise 3D positioning supplement. This segmentation allows the system to maintain simplicity by using GPS when possible while achieving high accuracy through the specialized acoustic reflection method when needed, particularly in environments where GPS is unavailable or insufficient.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If more sensors are added to the vehicle, then positioning capability is improved, but cost increases

Engineering Contradiction:
Improvepositioning capabilityVSAvoidnumber of sensors
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The invention makes the ground plane serve the positioning function by utilizing its natural reflective properties. Instead of adding expensive sensors to detect vertical position or to create additional signal paths, the system uses the existing ground plane to reflect signals and create virtual image receivers. This self-service approach allows the environment itself to provide the additional positioning capability needed, eliminating the need for additional sensors.

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 allows for accurate three-dimensional positioning of a user device with reduced system complexity and cost, ensuring functionality in various environments, including those with limited GPS reception, by utilizing time synchronization and acoustic signals, and accounting for potential errors in signal reflection.

Implementation Method 1

at least one of the first and second receiver in the vehicle receives and identifies a reflected positioning signal having been reflected at a ground surface before reaching the receiver

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3385745B1Method and system for determining the position of a user device in relation to a vehicle
Publication Date: 2021.03.03 VOLVO CAR CORP
  • EP3385745B1 patent drawingFigure 1
  • EP3385745B1 patent drawingFigure 2
  • EP3385745B1 patent drawingFigure 3~4

AI summary

There is provided a method for determining a position of a user device in relation to a vehicle, the vehicle comprising a first and a second receiver. The method comprises transmitting a positioning signal by the transmitter comprised in the user device, receiving the positioning signal by the first receiver and by the second receiver being arranged at a distance from the first receiver; in at least one of the first and second receiver, receiving and identifying a reflected positioning signal having been reflected at a ground surface before reaching the receiver; performing time synchronization between the transmitter and the first and second receiver; determining a position of the user device in a three-dimensional coordinate system based on the time-of-flight of the positioning signal received in the first and second receiver and on the time-of-flight of at least one reflected positioning signal received by at least one of the first and second receiver.