Self-Position Estimation Using Confidence-Based Sensor Selection

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Solution Overview

Problem

Existing position estimation devices face accuracy degradation when estimating self-position using state amounts from sensors, particularly during constant speed linear motion where observation values from acceleration sensors remain constant, leading to decreased accuracy in acceleration bias, gravitational acceleration, and speed estimates.

Innovation Solution

A position estimation device comprising a state-amount estimation unit, a confidence-degree calculation unit, and a self-position estimation unit, which estimates state amounts for sensors, calculates confidence degrees for these estimates, and selects target sensors based on confidence degrees to improve self-position estimation accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the position estimation device uses state amounts from sensors (acceleration, angular velocity) for self-position estimation, then the estimation can be performed continuously, but the accuracy degrades during constant speed linear motion when observation values remain constant

Engineering Contradiction:
Improvecontinuity of position estimationVSAvoidaccuracy of state amount estimation
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the parameter being estimated from raw sensor observation values to state amounts (acceleration bias, gravitational acceleration, speed) that represent the underlying physical conditions. By estimating these parameters and using them to correct sensor readings, the system maintains accuracy even when observation values become constant during uniform motion.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by using the estimated state amounts to correct the sensor observation values. The estimated acceleration bias and gravitational acceleration are fed back to adjust the raw acceleration sensor readings, creating a closed-loop system that compensates for sensor errors and maintains estimation accuracy over time.

Inventive Principle:
Principle #23Feedback

2Duration of action of moving object

If the position estimation device uses state amounts with low confidence (estimated from constant observation values), then the estimation system can operate without interruption, but the self-position estimation accuracy decreases

Engineering Contradiction:
Improvecontinuous operation of position estimationVSAvoidaccuracy of self-position estimation
Core Design Contradiction:
Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The patent makes the position estimation system dynamic by adjusting which sensors and state amounts are used based on their confidence levels. When confidence in state amount estimates is low (such as during constant speed linear motion), the system dynamically switches to rely more on image-based estimation and other sensors with higher confidence, rather than continuously using the low-confidence state amounts.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by treating different sensors and state amounts differently based on their individual confidence levels. Instead of uniformly using all available data, the system selectively weights or excludes specific sensors and state amounts depending on their current reliability, allowing high-confidence data to dominate the estimation while low-confidence data is minimized or excluded.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3792874B1Position estimation device, position estimation method, and computer program
Publication Date: 2025.04.23 KK TOSHIBA
  • EP3792874B1 patent drawingFigure 1
  • EP3792874B1 patent drawingFigure 2
  • EP3792874B1 patent drawingFigure 3

AI summary

A position estimation device (50) according to an embodiment of the present disclosure is provided for estimating a self-position of a moving object device (10) provided with one or more sensors (22). The position estimation device includes a state-amount estimation unit (60), a confidence-degree calculation unit (62), and a self-position estimation unit (64). The state-amount estimation unit (60) estimates a state amount representing a state of each sensor based on an observation value of the corresponding sensor. The confidence-degree calculation unit (62) calculates a confidence degree representing a degree of confidence of the state amount of each sensor. The self-position estimation unit (64) selects one or more target sensors from among the sensors based on the confidence degree of the state amount of each sensor, and estimates the self-position based on the observation value and the state amount of each of the selected target sensors.