Cabin Radar Reflector Layout for Rear Seat Occupant Detection
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Solution Overview
Problem
Existing vehicle sensing systems using radar sensors face challenges in effectively detecting occupants in all regions of a vehicle's interior, particularly due to noise from multiple reflections and limited direct line of sight to rear seats.
Innovation Solution
A vehicular radar sensing system that includes a radar sensor and a reflector with radar-reflective portions, where the radar sensor transmits radio signals that are reflected by the reflector to specific regions of interest within the vehicle, improving resolution and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a radar sensor is used to detect occupants in all regions of the vehicle interior, then the coverage area is improved, but noise from multiple reflections increases and direct line of sight to rear seats is limited
Solution Approach 1:
The vehicle interior is divided into multiple regions of interest (front seat region, rear seat region, etc.), and separate reflector portions are assigned to each region. This segmentation allows the radar sensor to target specific areas independently, improving detection coverage while managing noise by focusing energy where needed rather than broadcasting omnidirectionally.
Solution Approach 2:
Different portions of the reflector are designed with specific reflective properties tailored to their designated regions of interest. The reflector has non-uniform structure where each local portion optimizes signal reflection for its specific target area, thereby improving detection quality in each zone while minimizing unwanted reflections from other areas.
2Area of stationary object
If a radar sensor transmits signals to all regions of the vehicle interior, then the detection coverage is improved, but the resolution and signal quality deteriorate due to noise from multiple reflections
Solution Approach 1:
The reflector is segmented into multiple discrete portions, each responsible for a specific region of interest. This segmentation enables the radar system to achieve high resolution in each targeted region by concentrating reflected energy back to the sensor, while avoiding the resolution degradation that would result from omnidirectional transmission and reception of multiple unwanted reflections.
Solution Approach 2:
The harmful multiple reflections are extracted and redirected by the reflector portions toward the radar sensor in a controlled manner. By strategically placing reflector portions at specific locations and orientations, the system extracts useful reflected signals from target regions while excluding unwanted reflections from other areas, thereby maintaining high measurement precision across the coverage area.
3Ease of operation
If the radar sensor is positioned to directly observe rear seats, then the direct line of sight is improved, but the structural constraints of the vehicle interior are worsened
Solution Approach 1:
Reflector portions are introduced as intermediary elements between the radar sensor and the rear seat region. These reflectors act as mediators that redirect radar signals around structural obstacles (such as the dashboard and front seats) to reach the rear seats, thereby providing effective line of sight without requiring physical changes to the vehicle interior structure.
Solution Approach 2:
Instead of attempting to achieve direct line of sight through linear positioning, the system uses reflector portions positioned at elevated locations (such as the roof or upper dashboard area) to create indirect signal paths. This dimensional approach allows the radar sensor to observe rear seats by reflecting signals off overhead surfaces, bypassing the blockage created by the vehicle's structural layout.
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
The system enhances radar performance by focusing beams on specific regions of interest, allowing for accurate detection of occupants in all areas of the vehicle interior without blockage, thereby improving occupant monitoring capabilities.
Implementation Method 1
The radar sensor transmits radio signals and receives radio signals. The received radio signals include radio signals that reflect off the plurality of radar-reflective portions of the reflector toward the radar sensor.
Implementation Method 2
Each radar-reflective portion of the plurality of radar-reflective portions of the reflector reflects radio signals transmitted by the radar sensor toward a respective region of interest of a plurality of regions of interest within the interior cabin of the vehicle.
Data Source
AI summary
A vehicular radar sensing system includes a radar sensor and a reflector disposed at an interior cabin of a vehicle. The reflector includes a plurality of radar-reflective portions. Transmitted radio signals from the radar sensor reflect off the radar-reflective portions of the reflector toward respective regions of interest of a plurality of regions of interest within the vehicle. Each radar-reflective portion of the plurality of radar-reflective portions of the reflector reflects transmitted radio signals toward a different respective region of interest of the plurality of regions of interest. Received radio signals include radio signals that reflect off the reflector toward the radar sensor. The vehicular radar sensing system, responsive to processing of captured radar data, determines presence of an occupant of the vehicle at one of the regions of interest of the plurality of regions of interest.