Vehicle Occupant Detection Using Low-Frequency Electromagnetic Waves
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Solution Overview
Problem
Existing techniques for detecting a person in a vehicle using high-frequency electromagnetic waves result in larger circuit sizes due to the need for high-frequency detection, which is inefficient and impractical for miniaturization.
Innovation Solution
A detection apparatus that transmits and receives electromagnetic waves at lower frequencies, utilizing a detection transmitter and receiver to compare changes in reception intensity over time, allowing for the determination of a person's presence within the vehicle, thereby reducing the circuit size and using waves at frequencies lower than conventional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency electromagnetic waves (approximately 10 GHz) are used to detect a person in a vehicle based on reflected wave intensity, then the detection accuracy is improved, but the circuit size increases
Solution Approach 1:
The patent changes the detection parameter from reflected wave intensity to wave transmission characteristics (phase or amplitude changes). This parameter change allows detection to be performed using lower frequency electromagnetic waves, which reduces the circuit size while maintaining detection accuracy. The transmitter and receiver are positioned to detect waves that pass through the vehicle interior, and the determination portion analyzes phase or amplitude changes in these transmitted waves to detect the presence of a person.
2Reliability
If high-frequency electromagnetic waves are transmitted to detect a person, then the reflected wave intensity is sufficient for detection, but the device complexity increases
Solution Approach 1:
The patent replaces the mechanical approach of using high-frequency waves with a wave-based approach using lower frequency electromagnetic waves. Instead of relying on reflected wave intensity measurement which requires complex high-frequency circuitry, the system uses phase or amplitude modulation of lower frequency waves that pass through the detection space, simplifying the overall device complexity while maintaining reliable detection.
3Ease of operation
If reflected wave intensity measurement is used to detect a person, then the detection method is straightforward, but the frequency must be high which increases circuit size
Solution Approach 1:
The patent introduces an intermediary measurement approach by using phase or amplitude changes of transmitted waves as a mediator between the electromagnetic wave and the detection result. Instead of directly measuring reflected wave intensity which requires high frequency, the system measures the modulation effects (phase or amplitude changes) caused by the person's presence on lower frequency transmitted waves, thereby simplifying the circuit while maintaining detection capability.
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
Enables the detection of a person in a vehicle using lower frequency electromagnetic waves, reducing the size of the detection circuit and simplifying processing, while accurately determining presence even in cases of slight movements like breathing, thus facilitating accurate and compact person detection.
Implementation Method 1
a transmitter that transmits an electromagnetic wave toward an inside of a vehicle; a receiver that receives the electromagnetic wave transmitted by the transmitter
Implementation Method 2
the presence or absence of a person is detected based on the reception intensity of the electromagnetic wave received by way of the person located between the transmitter and the receiver
Data Source
AI summary
A detection apparatus includes: a transmitter transmitting an electric wave toward an inside of a vehicle; a receiver receiving the transmitted electric wave each time the transmitter transmits the electric wave, and performing output in accordance with reception strength of the received electric wave; and a determination portion, based on the reception strength of the electric wave received by the receiver, comparing a change mode of the electric wave received by the receiver changing over time to a predetermined reference mode and determining whether a person is present between the receiver and the transmitter.