Vehicle Occupancy Radar Using Accelerometer Vibration Filtering

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Solution Overview

Problem

Current radar-based occupant detection systems in vehicles are hindered by high integration costs and sensitivity to external influences like wind, traffic, and engine vibrations, leading to false positive classifications.

Innovation Solution

Incorporating accelerometer data into the radar sensor system's processing circuitry to filter out external vibrations and improve classification accuracy by generating occupancy status signals that differentiate between internal and external motions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If radar sensors are used for occupancy detection, then contactless and invisible measurement is achieved, but sensitivity to external influences like wind, traffic, and engine vibrations causes false positive classifications

Engineering Contradiction:
Improveoccupancy detection accuracyVSAvoidsensitivity to external influences
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces accelerometer data as an intermediary element that mediates between the radar sensor signals and the occupancy detection algorithm. The accelerometer measures vehicle motion and vibration independently, providing reference data that helps distinguish between external disturbances (affecting both radar and accelerometer) and actual occupant presence (affecting radar but not accelerometer). This intermediary measurement enables the system to filter false positives while maintaining radar's contactless detection capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback by continuously monitoring vehicle motion through accelerometers and using this information to adjust the interpretation of radar signals. The accelerometer data provides real-time feedback about external conditions, allowing the occupancy detection algorithm to dynamically compensate for vibrations and movements. This feedback loop enables the system to maintain high reliability despite sensitivity to external influences.

Inventive Principle:
Principle #23Feedback

2Reliability

If separate radar sensors are installed in every single seat, then occupancy detection coverage is improved, but integration costs increase significantly

Engineering Contradiction:
Improveoccupancy detection coverageVSAvoidintegration cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent makes the radar sensor universal by enabling a single radar unit to serve multiple seats simultaneously. Instead of requiring dedicated radar sensors for each seat, the system uses one or a few radar sensors that can detect occupants across multiple seating positions. This is achieved through signal processing that can distinguish between occupants in different locations based on the radar return patterns, thereby reducing the total number of sensors needed while maintaining comprehensive coverage.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system merges the functionality of multiple radar sensors into a single integrated solution. By combining the detection capabilities of one or a few radar sensors with multi-seat coverage and using accelerometer data to enhance discrimination between different seating positions, the system achieves the functional equivalence of multiple separate sensors at lower cost. This merging approach reduces integration complexity and manufacturing expenses.

Inventive Principle:
Principle #5Merging (Combining)

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

Enhances the robustness of radar-based occupant detection and classification by reducing false positives and improving the system's ability to distinguish between internal and external influences, thereby enhancing the accuracy of occupant detection and vital sign monitoring.

Implementation Method 1

an antenna system for illuminating at least one occupiable position within the vehicle with an outgoing radar signal; at least one sensor for receiving at least one sensor signal reflected as a result of the outgoing radar signal

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

obtaining accelerometer data value from at least one accelerometer, said accelerometer data containing information regarding vibration or motion of said automotive vehicle

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Data Source

PatentEP3191864B1Radar sensing of vehicle occupancy
Publication Date: 2019.10.30 IEE INT ELECTRONICS & ENG SA
  • EP3191864B1 patent drawingFigure 1

AI summary

A method for sensing occupancy status within an automotive vehicle uses a radar sensor system comprising an antenna system, at least one sensor and processing circuitry. The method comprises illuminating, using the antenna system, at least one occupiable position within the vehicle with an outgoing radar signal; receiving, using at least one sensor, at least one sensor signal reflected as a result of the outgoing radar signal, obtaining accelerometer data value from at least one accelerometer, said accelerometer data containing information regarding vibration or motion of said automotive vehicle and supplying said accelerometer data to said processing circuitry; operating the processing circuitry for generating,based on the at least one sensor signal and on the accelerometer data, one or more occupancy status signals, the occupancy status signal indicating a property related to said at least one occupiable position.