Vehicle Occupant Detection Using Radio Wave Reflection
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Solution Overview
Problem
Existing occupant detection systems in vehicles face challenges in accurately detecting occupants seated adjacent to seat doors due to low detection ratios, particularly when using high-frequency radio waves, which increase circuit complexity and reduce detection efficiency.
Innovation Solution
An occupant detection system that uses a transmitter adjacent to one side of a vehicle and a receiver on the opposite side behind the seat to transmit and receive radio waves through the occupant, allowing for detection even when seated next to a seat door, utilizing a lower frequency radio wave to reduce circuit complexity and improve detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency radio waves are used for occupant detection, then detection precision may be improved, but device complexity increases
Solution Approach 1:
The patent changes the frequency parameter of the radio wave from high frequency to lower frequency (e.g., VHF band). This parameter change reduces circuit complexity while maintaining effective occupant detection through the use of appropriate antenna designs and reception intensity analysis adapted for the lower frequency range.
2Reliability
If radio wave transmission is used for occupant detection, then detection capability is achieved, but detection ratio decreases when seat door is open
Solution Approach 1:
The patent uses the seat door itself as an intermediary reflective surface. By detecting radio waves reflected from the seat door, the system maintains detection capability even when the door is open, transforming the open door from a detection obstacle into a useful reflective element for indirect occupant detection.
Solution Approach 2:
The patent extends detection from direct line-of-sight (one dimension) to include indirect paths via reflection (multiple dimensions). By utilizing reflected radio waves from the seat door, the system detects occupants in scenarios where direct transmission is blocked, adding spatial dimensionality to the detection approach.
3Area of stationary object
If transmitter and receiver are positioned to detect occupants, then detection coverage is achieved, but detection accuracy decreases for seats adjacent to doors
Solution Approach 1:
The patent dynamically adapts the detection method based on seat door status. When a seat door is detected to be open, the system switches to using reflected radio wave detection for adjacent seats, while maintaining direct detection for other seats. This dynamic adaptation optimizes detection accuracy across all seating positions.
Solution Approach 2:
The patent segments the detection approach by seat position and door status. Different detection methods are applied to different seats depending on their proximity to open doors, allowing optimized detection accuracy for each segment while maintaining overall system coverage.
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 occupants seated adjacent to seat doors with a higher detection ratio without increasing circuit complexity, using a lower frequency radio wave that passes through the occupant, enhancing detection accuracy and reliability.
Implementation Method 1
a transmitter provided adjacent to a first side face of the vehicle before a predetermined seat of the vehicle to successively transmit a radio wave over a range covering a seat door located on a second side face of the vehicle and in a same row as the predetermined seat
Implementation Method 2
a receiver provided adjacent to the second side face behind the predetermined seat to successively receive the radio wave transmitted from the transmitter
Data Source
AI summary
An occupant detection system includes a transmitter provided adjacent to a first side face of a vehicle before a predetermined seat and successively transmitting a radio wave over a range covering a seat door located on a second side face of the vehicle and in a same row as the predetermined seat, a receiver provided adjacent to the second side face behind the predetermined seat and receiving the radio wave transmitted from the transmitter, and an occupant detection device including a reception intensity acquirer, an occupant detector, an opening and closing detector. The reception intensity acquirer successively acquires a reception intensity of a radio wave successively received by the receiver. The occupant detector detects an occupant in the vehicle according to the reception intensity of the radio wave received by the receiver while the opening and closing detector detects that the seat door is open.