Seat Occupancy Detection via Electromagnetic Antenna Coupling
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Solution Overview
Problem
Existing seat occupancy detection systems face challenges in reliably differentiating between a person and objects, are prone to interference from environmental influences, and require significant installation effort, especially in environments with multiple seats.
Innovation Solution
The method utilizes UHF radio waves emitted from a transmitting antenna, which are reflected by a human body and measured by an adjacent receiving antenna, allowing for reliable detection of seat occupancy with minimal transmission power and no structural changes, using a near-field detection method that optimizes electromagnetic coupling between antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If force or pressure sensors are used to detect seat occupancy, then the detection can be implemented, but the installation effort and cabling requirements increase substantially
Solution Approach 1:
The patent replaces mechanical force/pressure sensors with an electromagnetic field-based detection system using transmitting and receiving antennas. This substitution eliminates the need for mechanical contact sensors and their associated cabling, reducing installation complexity while maintaining occupancy detection capability through measurement of electromagnetic coupling changes
Solution Approach 2:
The antenna system serves multiple functions: it detects occupancy through coupling measurement, differentiates between persons and objects using polarization analysis, and can potentially serve as part of the seat structure itself. This multi-functionality reduces the need for separate dedicated sensor systems and their associated installation requirements
2Ease of manufacture
If weight-based sensors are used, then occupancy detection is simple, but differentiation between persons and objects becomes unreliable
Solution Approach 1:
The patent changes the detection parameter from weight alone to electromagnetic coupling characteristics including amplitude and polarization. By measuring how the coupling amplitude changes when a person versus an object is present, the system achieves reliable differentiation while maintaining simple implementation through standard antenna components
Solution Approach 2:
The electromagnetic field acts as an intermediary between the antennas and the object being detected. The field interacts differently with persons (water-containing, conductive) versus objects (non-conductive), and this interaction modulates the coupling between antennas, enabling differentiation without direct contact or complex sensors
3Reliability
If optical or acoustic sensors are used, then occupancy detection can be achieved, but the system complexity and cost increase
Solution Approach 1:
The patent substitutes optical or acoustic sensor systems with electromagnetic antenna-based detection. This replacement uses standard RF components rather than complex optical arrays or acoustic transducers, reducing system complexity and cost while achieving reliable occupancy detection and object differentiation through electromagnetic coupling measurements
4Reliability
If high transmit power is used in RF systems, then detection range is improved, but electromagnetic radiation exposure and interference risk increase
Solution Approach 1:
The patent uses the natural electromagnetic coupling between antennas as a reference baseline, and detects occupancy by measuring deviations from this baseline coupling. This approach allows detection with minimal transmit power since the system relies on measuring coupling changes rather than detecting weak reflected signals, thereby reducing electromagnetic exposure while maintaining detection reliability
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 accurate and efficient detection of seat occupancy with low electromagnetic exposure, minimal installation effort, and reduced interference, allowing for differentiation between conductive and non-conductive objects, and can be retrofitted without altering the existing structure.
Implementation Method 1
UHF radio waves of suitable frequency (s) are emitted from a transmitting antenna, which are reflected by the (human) body to be detected
Implementation Method 2
detect the occupancy of a seat via the characteristic change in the electromagnetic coupling between two adjacent antennas arranged in or under the seat
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
With increasing demands on transport capacity, safety, and logistics, systems for reliably detecting seat occupancy in vehicles, auditoriums, etc., are becoming increasingly important. Solutions that can be easily retrofitted into existing systems are of particular interest, although the use of previously known standard solutions is hampered by technical reasons as well as high installation costs. To remedy this, the invention proposes to detect the occupancy status of a seat (1) by measuring the characteristic changes in the electromagnetic coupling (23) between adjacent antennas (21, 22) integrated in or under the seat in the presence of a proximal (human) body (11).From the relations (51, 52, 61, 62) between emitted and received radio waves (211, 221) the occupancy status of the seat (1) can thus be reliably determined simply and with minimal transmission power.