Vehicle Surface Detection for Flat-Surface Sensor Calibration

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Solution Overview

Problem

Existing vehicle-mounted accelerometers, both built-in and aftermarket, face challenges in accurately determining the relationship between their coordinate systems and the vehicle's coordinate system, necessitating a valid translation matrix, which requires a flat surface for calibration, but such surfaces are difficult to reliably detect.

Innovation Solution

A surface detection device that utilizes GNSS and gyro data points to determine if the vehicle is on a flat surface by analyzing buffered data points, calculating total vertical difference values, and normalized average acceleration values to ensure accurate calibration of gyro devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a translation matrix is determined during manufacturing for built-in accelerometers, then the relationship between accelerometer coordinate system and vehicle coordinate system is known, but it may be necessary to determine whether the calibration is still valid

Engineering Contradiction:
Improvecalibration validityVSAvoidcalibration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary detection of surface flatness using buffered motion data before initiating calibration procedures. This preliminary action filters out unsuitable calibration conditions in advance, preventing wasted calibration attempts and reducing overall calibration time while ensuring reliability.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If aftermarket accelerometer devices are attached to the vehicle, then they can be installed after production, but the geometric relation between the accelerometer coordinate system and vehicle coordinate system is unknown and needs calibration

Engineering Contradiction:
Improvedevice compatibilityVSAvoidcalibration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system uses the vehicle's existing motion data from GNSS and built-in sensors to automatically detect surface flatness and assist in the calibration process. This self-service approach reduces calibration complexity by providing automated detection and analysis capabilities without requiring additional specialized equipment or manual intervention.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If the vehicle is placed on a level surface for calibration, then accurate calibration can be performed, but it is necessary to detect whether the vehicle is on a flat surface

Engineering Contradiction:
Improvecalibration accuracyVSAvoidflat surface detection difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The system introduces an intermediary detection layer that uses buffered motion data from GNSS and vehicle sensors to indirectly detect surface flatness. Instead of directly measuring surface inclination, the system analyzes vehicle motion patterns and acceleration data as intermediaries to infer whether the vehicle is on a flat surface, thereby reducing detection difficulty while maintaining calibration accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If motion data is buffered and analyzed only when the vehicle stops, then surface detection can be performed, but data collection must wait for vehicle stop

Engineering Contradiction:
Improvesurface detection accuracyVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary buffering of motion data during vehicle operation, preparing the data set in advance. When the vehicle stops, the pre-buffered data is immediately available for analysis without requiring additional data collection time. This preliminary action eliminates detection delays while maintaining measurement precision through thorough pre-collected data sets.

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

Enables reliable detection of a flat surface for calibration, ensuring accurate translation matrix determination without requiring access to OEM proprietary data, applicable to aftermarket devices with GNSS and gyro sensors, and allowing periodic recalibration to maintain gyro device accuracy.

Implementation Method 1

The gyro device may comprise three accelerometer units, configured to determine an acceleration of a respective axes of a coordinate system (6) of the gyro device (3)

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

The GNSS device (4) may be configured to provide four to six GNSS data points, related to received GNSS signals

Methodology Applied
Scientific EffectGNSS signal reception:

Implementation Method 3

calculate a normalized average acceleration value of acceleration values of the buffered gyro data points. The control unit (5) may determine whether the normalized average acceleration value of the buffered gyro data points satisfies a predefined normalized average acceleration value condition

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP4700331A1Surface detection device, a vehicle comprising a surface detection device, a method to operate a surface detection device, a computer program product and computer-readable memory
Publication Date: 2026.02.25 CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH
  • EP4700331A1 patent drawingFigure 1
  • EP4700331A1 patent drawingFigure 2
  • EP4700331A1 patent drawing

AI summary

Surface detection device, a vehicle comprising a surface detection device, a method to operate a surface detection device, a computer program product and computer-readable memory The invention is concerned with a surface detection device (2) configured to detect a predefined surface property of a surface (8) under a vehicle (1). The surface detection device (2) is configured to perform a surface recognition procedure, wherein the surface detection device (2) is configured to receive data points during an operation of the vehicle (1) and to add at least some of the data points to a buffer of the surface detection device (2), wherein the data points relate to a motion of the vehicle (1). The surface detection device (2) is configured to analyze the buffered data points, when the surface detection device (2) recognizes a stop of the vehicle (1). The surface detection device (2) is configured to detect the predefined surface property of the surface (8), when the analysis of the buffered data points reveals that a predefined surface condition is satisfied.