Radio Wave Sensor Antenna Layout for Rear-Seat Occupant Detection
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Solution Overview
Problem
Existing occupant detection devices in vehicles require multiple image sensors to detect and identify occupants, leading to inefficiencies and blind spots, particularly for children sitting in rear seats.
Innovation Solution
A radio wave sensor system with a transmission antenna and reception antenna elements arranged differently in the vehicle's width and height directions to emit and receive radio waves, allowing for the detection and identification of all occupants using frequency modulation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple image sensors are disposed to detect all occupants, then detection coverage is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical/optical image sensor system with a radio wave-based detection system. The radio wave sensor emits radio waves that penetrate through the front seat to detect occupants in the rear seat, eliminating the need for multiple image sensors and their associated complex mounting and calibration systems.
Solution Approach 2:
The radio wave sensor performs multiple detection functions simultaneously - it can detect both front seat and rear seat occupants using a single sensor unit. The sensor emits radio waves in multiple directions and processes reflected waves to identify occupants across different seating positions, providing universal detection capability.
2Measurement precision
If image sensors are positioned to cover front seats, then front seat detection is improved, but rear seat detection capability deteriorates due to blind spots
Solution Approach 1:
The patent transitions from optical detection (line-of-sight requirement) to radio wave detection (penetration capability). Radio waves can pass through the front seat structure and reach the rear seat area, effectively adding a new dimension of detection capability that overcomes the blind spot problem inherent in optical image sensors.
Solution Approach 2:
The radio wave acts as an intermediary that can penetrate through the front seat (which blocks optical sensors). The transmission antenna emits radio waves that pass through the front seat, and the reception antenna receives reflected waves from rear seat occupants, enabling detection without direct line of sight.
3Device complexity
If transmission antenna elements are arranged in one direction and reception antenna elements in the same direction, then system simplicity is improved, but detection accuracy deteriorates
Solution Approach 1:
The patent employs asymmetric arrangement of antenna elements - transmission antenna elements are positioned at different locations, and reception antenna elements are positioned at different locations, creating an asymmetric configuration that optimizes the detection of reflected radio waves from multiple directions and improves occupant position identification accuracy.
Solution Approach 2:
The patent positions transmission and reception antenna elements in different spatial dimensions and orientations. This multi-dimensional arrangement allows the system to receive reflected radio waves from various angles, improving the accuracy of determining occupant positions and characteristics.
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 effectively detects and identifies all occupants, including adults and children, within a vehicle interior by analyzing reflection waves, providing comprehensive occupancy information.
Implementation Method 1
a transmission antenna including a plurality of transmission antenna elements to emit a radio wave toward a presence allowable area
Implementation Method 2
a reception antenna including a plurality of reception antenna elements to receive a reflection wave of the radio wave emitted from the transmission antenna
Data Source
AI summary
A radio wave sensor includes: a transmission antenna that emits a radio wave toward a presence allowable area which is an area in which an occupant can be present in an area in a vehicle interior of a vehicle; and a reception antenna including a plurality of reception antenna elements that receives a reflection wave of the radio wave emitted from the transmission antenna. Positions of at least some of the plurality of reception antenna elements are arranged at least in other direction different from one direction between the vehicle height direction and the vehicle width direction.