Barometer Calibration via Charging Position for Accurate Height Sensing

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Solution Overview

Problem

Current electronic devices face inaccuracies in measuring atmospheric pressure due to measurement uncertainties in barometers, which can lead to significant errors in height calculations, especially when devices are movable relative to a stationary reference point, necessitating a method to calibrate and compensate for these uncertainties over time.

Innovation Solution

An electronic apparatus with movable and fixed devices, where the movable devices are electromagnetically coupled to a fixed device during charging, allowing for calibration of atmospheric pressure measurements using a reference value from a fixed barometer, periodically resetting measurement uncertainties by calculating and adjusting pressure differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If barometers are integrated in devices with standard manufacturing calibration, then manufacturing cost and complexity are reduced, but measurement precision deteriorates due to accumulated uncertainties of tens of pascals that lead to height errors of meters

Engineering Contradiction:
Improvebarometer integrationVSAvoidatmospheric pressure measurement
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The system performs preliminary calibration actions by detecting when movable devices are placed on the fixed device (indicating same altitude) and automatically adjusting calibration parameters at these predetermined moments, rather than requiring manual calibration at factory settings only

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors atmospheric pressure measurements from multiple barometers and uses feedback loops to detect discrepancies, automatically triggering calibration routines when devices are detected at the same altitude to correct accumulated uncertainties

Inventive Principle:
Principle #23Feedback

2Measurement precision

If barometers are calibrated only immediately after manufacturing, then initial measurement accuracy is improved, but measurement precision deteriorates over time due to barometer wear and environmental conditions causing variations of about 1 hPa every year

Engineering Contradiction:
Improveatmospheric pressure measurementVSAvoidbarometer operational life
Core Design Contradiction:
Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The system implements periodic calibration by automatically detecting when movable devices are placed on the fixed device and performing calibration adjustments at these periodic intervals, counteracting the gradual drift caused by barometer aging and environmental exposure

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system performs self-calibration automatically without requiring user intervention or factory recalibration services, using the predetermined calibration positions (when devices are placed together) to autonomously correct its own measurement uncertainties over time

Inventive Principle:
Principle #25Self-service

3Device complexity

If standard barometers are used in movable devices, then device complexity is reduced, but measurement precision deteriorates when devices are moved relative to reference points, causing height measurement errors of meters instead of the required tens of centimeters

Engineering Contradiction:
Improvebarometer systemVSAvoidheight measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The fixed device acts as an intermediary reference point with known calibration parameters, allowing movable devices to periodically synchronize their barometer readings against this stable reference when placed together, thereby maintaining measurement precision without adding complex calibration hardware to each movable device

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method ensures accurate and consistent atmospheric pressure measurements across all devices, reducing errors and providing a common reference for precise height calculations, even when devices are not simultaneously charged.

Implementation Method 1

a fixed barometer (18) configured to measure a atmospheric pressure value

Methodology Applied
Scientific EffectAtmospheric pressure measurement:

Implementation Method 2

The movable barometers 16a and 16b are configured to measure respective atmospheric pressure values, correlated to the respective altitudes whereat the movable barometers 16a, 16b are placed

Methodology Applied
Scientific EffectAtmospheric pressure measurement:

Implementation Method 3

the movable devices are electromagnetically coupled to a fixed device during charging

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Data Source

PatentEP4239305B1Method for determining calibrated values of atmospheric pressure and related electronic apparatus
Publication Date: 2024.12.18 STMICROELECTRONICS SRL
  • EP4239305B1 patent drawingFigure 1~5
  • EP4239305B1 patent drawingFigure 2
  • EP4239305B1 patent drawingFigure 3

AI summary

Method (50) for determining a first (P1') and a second (P2') calibrated value of atmospheric pressure, performed by an electronic apparatus (10) comprising a fixed device (14) and a first (12a) and a second (12b) movable device comprising respectively a first (16a) and a second (16b) movable barometer. The method (50) comprises: determining (S10) whether the movable devices are being inductively charged by the fixed device; if so, acquiring (S12) respective measured values of atmospheric pressure (P1, P2) through the movable barometers (16a, 16b), and a reference value of atmospheric pressure (Prif) in a common reference point of the electronic apparatus (10), the movable barometers being at respective predefined height differences (Δh) with respect to the common reference point; calculating (S14) respective pressure differences (ΔP1, ΔP2) as a function of the measured values of atmospheric pressure and of the reference value of atmospheric pressure; and when the movable devices are not being charged, acquiring (S20) new measured values of atmospheric pressure through the movable barometers, and determining (S20) the respective calibrated values of atmospheric pressure as a function of the new measured values of atmospheric pressure and of the pressure differences.