Mobile Robot Localization Using Beacon-Sensor LOS Comparison

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Solution Overview

Problem

Conventional moving robots face challenges in accurately determining their location due to the difficulty in distinguishing between Line of Sight (LOS) and Non-Line of Sight (NLOS) radio signals, which affects their autonomous navigation and location recognition.

Innovation Solution

The moving robot employs a RF receiver to track distance and radio direction from beacons, compares beacon distance with sensor data, and uses a control method that includes radio direction acquisition, first and second distance tracking, and comparison steps to enhance location accuracy by distinguishing between LOS and NLOS signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single sensor is used for RF-based location recognition, then device complexity is reduced, but measurement precision deteriorates due to inability to distinguish LOS and NLOS signals

Engineering Contradiction:
Improvesensor quantityVSAvoidlocation recognition accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent combines multiple sensors (RF receiver, distance sensor, and optionally camera module) into an integrated location recognition system. The RF receiver captures radio direction data from beacons, the distance sensor measures actual distance to objects, and these data are merged and compared to determine LOS/NLOS conditions and calculate accurate location information.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces comparison logic as an intermediary process that mediates between RF-based distance calculation and sensor-based distance measurement. This intermediary comparison mechanism determines whether the RF signal is LOS or NLOS by checking consistency between the two distance measurements, thereby improving location accuracy without simply adding more sensors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If RF-based location recognition is used without signal type differentiation, then device complexity is reduced, but reliability deteriorates due to NLOS signal interference

Engineering Contradiction:
Improvesignal processing complexityVSAvoidlocation recognition reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments RF signals into two categories: LOS (Line of Sight) and NLOS (Non-Line of Sight) signals. By dividing the signal processing into these two distinct paths, the system can apply different handling strategies - using RF direction data for LOS signals and relying more on sensor data for NLOS signals - thereby improving reliability without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial differentiation - it doesn't require complex signal processing for all signals, but only for distinguishing LOS from NLOS. Once this partial differentiation is achieved, the system uses straightforward comparison logic to determine which data source (RF or sensor) to trust, avoiding excessive processing complexity while improving reliability.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If multiple sensors and data comparison methods are employed, then location recognition accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvelocation recognition accuracyVSAvoidsystem structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a dynamic location recognition system that adapts its data source selection based on real-time conditions. The controller dynamically determines whether RF signals are LOS or NLOS by comparing distance measurements, and dynamically switches between using RF direction data and sensor data based on this determination, optimizing accuracy without requiring a fixed complex structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms where the distance sensor's measurement is used to verify and correct the RF-based location calculation. The comparison result feeds back into the location determination process, allowing the system to self-correct and improve accuracy. This feedback loop provides high accuracy without requiring a permanently complex system structure.

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

This approach improves the location recognition accuracy of the moving robot by effectively differentiating between LOS and NLOS signals, ensuring precise navigation and obstacle detection during autonomous operation.

Implementation Method 1

a RF receiver configured to track a distance and a radio direction to calculate a radio direction between the receiver and a RF beacon

Methodology Applied
Scientific EffectRadio frequency signal transmission and reception: Electromagnetic Induction

Data Source

PatentEP4180186B1Mobile robot and method for controlling same
Publication Date: 2025.12.03 LG ELECTRONICS INC
  • EP4180186B1 patent drawingFigure 1
  • EP4180186B1 patent drawingFigure 2
  • EP4180186B1 patent drawingFigure 3

AI summary

Disclosed is a control method of a moving robot configured to drive a work area where a plurality of beacons, the control method comprising a radio direction acquiring step of acquiring radio direction information from the beacons; a first distance tracking step of tracking first distance information between the moving robot and the beacons based on the radio direction information, after the radio direction acquiring step; a second distance tracking step of tracking second distance information between the moving robot and an object existing in the work area via a distance sensor provided in the moving robot; and a first comparison step of comparing the first distance information with the second distance information, wherein location recognition of the moving robot is performed based on the radio direction information, when the first distance is equal to the second distance based on the result of the first comparison step.