Elevator Positioning via Frequency Spectrum Footprinting
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Solution Overview
Problem
Radar-based elevator positioning systems face challenges with multi-path interference, leading to unstable and inconsistent signal strength, making it difficult to accurately determine the position of an elevator car within a shaft, especially when initial positioning is unknown or inconsistent.
Innovation Solution
The system generates and uses 'footprints' that represent frequency spectrum data at reference positions along the elevator shaft, allowing for comparison with real-time data to estimate the elevator car's position, thereby reducing the impact of multi-path interference and eliminating the need for initial height and speed knowledge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radar-based positioning is used in elevator shafts, then positioning capability is provided, but multi-path interference causes unstable and inconsistent signal strength reducing measurement reliability
Solution Approach 1:
The patent transforms the positioning problem from direct distance measurement to frequency spectrum analysis. By converting spatial information into spectral fingerprints and comparing frequency patterns, the system operates in a different dimensional space (frequency domain) where multi-path interference patterns are consistent and can be used for reliable positioning without directly measuring signal strength.
Solution Approach 2:
The system creates spectral fingerprint copies of the elevator shaft environment at different heights. These fingerprints serve as reference templates that are compared against real-time spectral data. By copying and storing the characteristic frequency patterns of the shaft structure, the system can identify position based on pattern matching rather than direct signal strength measurement, achieving reliability despite interference.
2Adaptability or versatility
If traditional radar positioning methods are used, then position detection is possible, but initial height and speed knowledge is required reducing system adaptability
Solution Approach 1:
The system enables the elevator car to determine its own position autonomously by comparing its current spectral fingerprint against stored reference fingerprints. The car self-identifies its position based on the unique frequency pattern it detects, without requiring external information about initial height or speed. This self-service capability eliminates dependency on initial conditions while maintaining simple operation.
Solution Approach 2:
The system performs preliminary spectral fingerprint collection and storage at various reference heights before actual positioning begins. By pre-capturing the frequency spectrum characteristics of the shaft at different positions and storing them as references, the system prepares the necessary data in advance. This preliminary action eliminates the need for real-time calculation of initial conditions during actual positioning operations.
3Measurement precision
If signal strength-based positioning is used, then position estimation is possible, but unstable signals result in positioning errors exceeding acceptable thresholds
Solution Approach 1:
The patent fundamentally changes the measurement parameter from signal strength (amplitude) to frequency spectrum characteristics. Instead of measuring how strong the reflected signal is, the system analyzes the frequency distribution and spectral patterns of the signal. This parameter transformation converts an unstable measurement (signal strength varies with interference) into a stable measurement (frequency patterns remain consistent despite interference variations), achieving sub-10mm positioning accuracy.
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 elevator car positioning with an error of less than 10 millimeters, improving reliability and applicability by consistently detecting radar signals and tracking the car's position without relying on initial conditions.
Implementation Method 1
a radar transceiver attached to the elevator car... determining reference frequency spectrum data... obtaining real-time frequency spectrum data
Implementation Method 2
determining a coarse position estimate... identifying a particular frequency peak... corresponding to a radar reflector positioned within the elevator shaft
Data Source
AI summary
Various embodiments are directed to determining an elevator car position within an elevator shaft using footprint representations or descriptions of frequency spectrum data at reference positions along the elevator shaft. In one aspect, an example method is provided. The method includes determining reference frequency spectrum data for each of a plurality of reference positions along the elevator shaft and generating a footprint associated with each reference position based at least in part on a plurality of frequency peaks within the reference frequency spectrum data for each reference positions. The method further includes obtaining real-time frequency spectrum data associated with the elevator car within the elevator shaft and determining an estimated position of the elevator car based at least in part on comparing the real-time frequency spectrum data with a plurality of footprints associated with the plurality of reference positions.