RF Seat Occupancy Sensing for Multi-Row Occupant Distinction
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Solution Overview
Problem
Existing vehicle seat occupancy sensors face challenges in accurately distinguishing between occupants, particularly when they are sitting close together or in multiple rows, and require multiple sensors per seat, which can be expensive.
Innovation Solution
A seat occupancy sensor system using RF sensors operates in two modes: a first mode for tracking occupant entry/exit based on velocity resolution when doors are open, and a second mode for distinguishing occupants in the cabin using range and angular resolution when doors are closed, utilizing adjustable chirp parameters and signal processing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors or capacitive sensors are used for each seat to detect occupancy, then occupancy detection accuracy is improved, but system cost increases due to requiring separate sensors for each seat
Solution Approach 1:
The patent applies universality by using a single RF sensor to perform multiple functions: detecting occupancy in multiple seats simultaneously, distinguishing between different occupants, and providing both presence/absence detection and occupant differentiation capabilities that would otherwise require multiple separate sensors
Solution Approach 2:
The patent merges the functions of multiple separate seat occupancy sensors into a single RF sensor system, combining detection capabilities for multiple seats and multiple occupants into one integrated sensor unit that reduces overall system complexity and cost
2Device complexity
If a single ultrasonic sensor is used to detect movements in multiple seats, then system cost is reduced, but measurement precision deteriorates due to inability to accurately distinguish between occupants sitting close together or in multiple rows
Solution Approach 1:
The patent transitions from ultrasonic sensing (acoustic dimension) to RF sensing (electromagnetic dimension), enabling the single sensor to achieve superior resolution and occupant distinction capability through radio frequency signal processing that can detect subtle differences in reflectors and multipath signatures
Solution Approach 2:
The patent changes the operating parameters by using RF signals with specific frequency ranges and modulation schemes that provide better resolution for distinguishing occupants. The system adjusts chirp parameters, signal processing techniques, and operational modes to optimize occupant distinction accuracy while maintaining cost-effectiveness
3Measurement precision
If RF sensors operate in high resolution mode to distinguish occupants sitting close together, then measurement precision is improved, but energy consumption increases
Solution Approach 1:
The patent implements dynamic operational modes that allow the RF sensor to switch between different resolution and energy consumption levels. The system can operate in a lower energy mode for basic occupancy detection and switch to high resolution mode only when occupant distinction is required, optimizing the balance between accuracy and energy usage
Solution Approach 2:
The patent uses parameter changes by adjusting RF signal characteristics such as chirp duration, bandwidth, and sampling rates based on operational requirements. These parameter adjustments enable the sensor to achieve high resolution occupancy distinction only when needed, reducing overall energy consumption while maintaining measurement precision when required
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
Improves accuracy in detecting and distinguishing vehicle occupants by optimizing sensor settings based on door status, reducing false positives and negatives, and enabling efficient use of a single sensor for multiple seats.
Implementation Method 1
at least one seat occupancy sensor configured to receive radio frequency (RF) signals within a passenger cabin of the vehicle
Data Source
Figure 1~2
Figure 3
AI summary
A seat occupancy sensor system and method that use radio frequency (RF) sensors to detect and distinguish vehicle occupants in a passenger cabin of a vehicle. The system may include one or more seat occupancy sensor(s) and a seat occupancy control module and can operate according to different operational modes based on the state of the vehicle doors. When one or more door(s) are open, the system and method may operate according to a first operational mode that keeps track of vehicle occupants entering and/or exiting the passenger cabin; and when there are no doors open, the system and method may operate according to a second operational mode that detects and distinguishes vehicle occupants in the passenger cabin, with the occupant count from the first mode being used as an input. These different operational modes can help improve the accuracy and/or performance of seat occupancy sensor system.