Frequency Scanning Radar for Vehicle Occupancy Detection
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Solution Overview
Problem
Current radar-based occupancy detection systems for vehicles are costly due to the need for multiple sensors per seat, and conventional foil-based systems struggle with out-of-position detection and high integration costs, while existing radar solutions lack reliability in distinguishing between occupants and external objects.
Innovation Solution
A radar sensor system with frequency-dependent beam steering, utilizing a single antenna system with frequency scanning to detect and classify occupants by analyzing motion patterns and breathing motions, allowing for cost-effective occupancy detection and classification across multiple seats without the need for separate sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single radar sensor is used for occupancy detection across multiple seats, then integration costs and material costs are reduced, but the ability to distinguish between occupants and external objects becomes less reliable
Solution Approach 1:
The patent implements dynamic beam steering by continuously scanning the radar beam across different angular positions to cover multiple seats. The beam direction is dynamically adjusted based on detected motion signals, allowing a single sensor to reliably track and distinguish multiple occupants from external objects through active beam manipulation rather than static coverage
Solution Approach 2:
The system employs periodic frequency modulation and beam scanning to interrogate different spatial zones. By periodically sweeping the beam across the seating area and analyzing returning signals at different frequencies and time intervals, the system can distinguish between stationary external objects and moving occupants, maintaining reliability while using a single cost-effective sensor
2Reliability
If separate radar sensors are used for each seat, then occupancy detection reliability is improved, but integration costs and material costs increase
Solution Approach 1:
The patent makes a single radar sensor universal by equipping it with frequency-dependent beam steering capability. This allows one sensor to perform the functions of multiple sensors by electronically directing its beam to different seats and scanning positions, thereby achieving multi-seat coverage without the need for multiple physical sensors, reducing costs while maintaining detection reliability
Solution Approach 2:
The system changes operational parameters (frequency, beam angle, scanning rate) to adapt to different detection scenarios. By modulating the frequency and steering the beam to different angular positions, a single sensor can effectively monitor multiple seats and distinguish occupants from external objects, replacing the need for multiple fixed sensors
3Ease of manufacture
If conventional foil-based pressure sensors are used, then occupancy detection is achieved, but out-of-position detection capability is lost
Solution Approach 1:
The patent transitions from the limited spatial coverage of foil sensors (only direct contact points) to three-dimensional volumetric coverage using radar waves. The frequency-dependent beam steering enables the system to scan and detect objects in multiple spatial dimensions and positions, including out-of-position occupants, by illuminating the entire seating volume rather than relying on contact points
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 approach enables reliable occupancy detection and classification for entire vehicle benches with reduced integration and material costs, while also providing vital sign monitoring capabilities, and can be validated with optical sensors for enhanced accuracy.
Implementation Method 1
an antenna system for which the main lobe direction (azimuth angle φ) is changing, preferably mostly linearly, over frequency
Implementation Method 2
Existing state of the art solutions use a conventional single frequency Doppler radar as a motion sensor
Implementation Method 3
The radar transmitter emits a wave field covering a space containing all permitted seats
Implementation Method 4
Radar systems can measure smallest motions within the range of micrometers
Data Source
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AI summary
A radar system with frequency scanning beam steering is described for in-vehicle occupant detection and classification for seat-belt reminder functionality (SBR) and airbag suppression. The system includes an antenna system for which the main lobe direction (azimuth angle o) is changing mostly linearly over frequency, a RF electronic transceiver electronic with at least one transmit channel and one or multiple receive channels with two outputs (l/Q) per channel. The data acquisition and signal processing/interpretation are made by a microcontroller system.