Automatic Pressure Sensor Calibration for Altitude Accuracy

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Solution Overview

Problem

Existing electronic devices face challenges in accurately determining absolute altitude using uncalibrated atmospheric pressure sensors, leading to large deviations and limited applications, especially indoors, due to the need for manual calibration which is inconvenient and time-consuming.

Innovation Solution

An automated method that calibrates the output of an absolute atmospheric pressure sensor by determining the device is at a known absolute altitude and outdoors, using a combination of motion sensor data and GNSS signals to calculate a reference pressure difference from mean sea level, which is then applied to subsequent measurements, eliminating the need for user input.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual calibration of atmospheric pressure sensors is performed by electronic device manufacturers, then measurement precision is improved, but productivity deteriorates due to lengthened production time

Engineering Contradiction:
Improvealtitude measurement accuracyVSAvoidproduction time
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The electronic device performs self-calibration by automatically determining that it is at ground level outdoors using motion sensor data and GNSS signals, then calculating and applying a reference pressure difference without requiring manufacturer intervention. This eliminates manual calibration while maintaining measurement precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs calibration actions automatically during device operation by detecting when the device is at ground level outdoors, before altitude measurements are needed. The reference pressure difference is calculated and stored in advance, eliminating the need for manual calibration steps during production or setup.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If manual calibration by electronic device users is performed, then measurement precision is improved, but ease of operation deteriorates due to inconvenience and restricted usage

Engineering Contradiction:
Improvealtitude measurement accuracyVSAvoiduser convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The calibration process is completely automated and performs itself without user intervention. The electronic device automatically detects ground level conditions using motion sensors and GNSS signals, calculates the reference pressure difference, and applies it to subsequent altitude measurements, eliminating the inconvenience of manual calibration while maintaining accuracy.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If uncalibrated atmospheric pressure sensors are used, then ease of operation is improved, but measurement precision deteriorates due to large deviations in determined altitudes

Engineering Contradiction:
Improveease of useVSAvoidaltitude measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system automatically performs calibration in advance by detecting ground level conditions and calculating reference pressure differences before altitude measurements are taken. This preliminary calibration action ensures measurement precision is achieved without requiring user awareness or intervention, maintaining ease of operation while eliminating large altitude deviations.

Inventive Principle:
Principle #10Preliminary action

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 provides accurate and reliable absolute altitude determination, reducing errors and eliminating the need for manual calibration, allowing for precise altitude measurement both indoors and outdoors, enhancing the convenience and accuracy of altitude data.

Implementation Method 1

Altitude may be determined by atmospheric pressure sensors of the electronic devices. Altitudes are calculated based on differences between atmospheric pressure sensor output and pressure at mean seal level.

Methodology Applied
Scientific EffectAtmospheric pressure measurement:

Implementation Method 2

receiving, at a GNSS sub-system of the electronic device in communication with the processor, GNSS signals

Methodology Applied
Scientific EffectGNSS signal reception:

Implementation Method 3

receiving, at the processor of the electronic device, motion sensor data of the electronic device indicative of a selected type of motion of the user

Methodology Applied
Scientific EffectMotion detection:

Data Source

PatentEP3440448B1Automatic pressure sensor output calibration for reliable altitude determination
Publication Date: 2021.05.05 FATHOM SYST INC
  • EP3440448B1 patent drawingFigure 1
  • EP3440448B1 patent drawingFigure 2
  • EP3440448B1 patent drawingFigure 3

AI summary

A method of calibrating output of an absolute atmospheric pressure sensor of an electronic device includes: determining, at a processor of the electronic device, that a location of the electronic device is at a known absolute altitude and outdoors; receiving, at the processor, a measured pressure from the absolute atmospheric pressure sensor; calculating, at the processor, a difference between the measured pressure and a reference pressure, the reference pressure determined by adjusting a mean sea level pressure based on the known absolute altitude relative to mean sea level at the location of the electronic device; storing the difference, in a memory of the electronic device; and applying the difference to the output of the absolute atmospheric pressure sensor; wherein determination that the electronic device is at the known absolute altitude and outdoors occurs without user input.