Systems and methods using multiple modalities for occupancy sensing
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Solution Overview
Problem
Existing systems fail to accurately determine the number of occupants in a location, which is crucial for optimizing building operations such as lighting, temperature, and energy usage, due to limitations in motion detection technologies like PIR sensors and RF wave systems that suffer from line of sight issues and multi-path reflections.
Innovation Solution
A hybrid system combining motion detectors, such as PIR sensors, and RF transceivers, using algorithms to fuse data from both modalities to provide an accurate occupant count, with the ability to recalibrate parameters based on each other's estimates to improve accuracy over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PIR sensors are used to detect occupancy, then motion detection capability is provided, but line of sight requirements limit detection accuracy
Solution Approach 1:
The patent combines PIR sensors and RF transceivers into a hybrid occupancy detection system. The PIR sensors provide motion detection capability while RF transceivers detect occupants without line-of-sight requirements, merging the strengths of both technologies to overcome individual limitations and improve overall detection accuracy.
2Object-affected harmful factors
If RF waves are used to detect occupants, then line of sight is not required, but multi-path reflections and near-far problems reduce measurement accuracy
Solution Approach 1:
The patent uses PIR sensor data as an intermediary to help resolve RF measurement ambiguities. The PIR sensors provide independent motion detection information that acts as a mediator to disambiguate RF signal sources, helping to distinguish between direct reflections and multi-path effects, thereby improving RF-based occupancy measurement accuracy.
3Measurement precision
If a single modality system is used, then device complexity is reduced, but occupancy measurement accuracy is insufficient
Solution Approach 1:
The patent implements a self-calibrating system where the PIR and RF subsystems use each other's data to improve their own accuracy. The algorithms automatically adjust and calibrate based on comparative analysis of both sensor modalities, reducing the need for manual configuration and maintenance while improving measurement precision.
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 precise occupancy tracking, enhancing energy efficiency and occupant comfort by accurately controlling building systems like HVAC, lighting, and ventilation, while minimizing errors in occupancy determination.
Implementation Method 1
passive infrared (PIR) sensors are a cost-efficient solution commonly deployed in buildings to control one or more systems in the building
Implementation Method 2
RF signals reflected from humans are detected and analyzed to measure occupancy of the space
Data Source
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AI summary
A system and method for determining a number of occupants at a location using multiple modalities. The method includes gathering a first data set with a motion sensor of the lighting system. A second data set is gathered with a transceiver of an RF subsystem. First and second estimates are calculated from the second data set using first and second algorithms. The first estimate and the second estimate are fused to create a fused occupant estimate. The first algorithm, the second algorithm, or both the first algorithm and the second algorithm are trained by inputting the second occupant estimate and/or the second set of data to recalibrate parameters of the first algorithm and/or inputting the first occupant estimate and/or the first set of data to recalibrate parameters during training of the second algorithm. A building control system can operated in response to the fused occupant estimate.