Elevator Radar Reflector Layout for Long-Shaft Positioning
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Solution Overview
Problem
Radar signal strength attenuation over long distances in elevator shafts poses challenges for accurate elevator positioning, constrained by regulations and limited space, leading to unreliable distance measurements.
Innovation Solution
A system with a plurality of radar reflectors positioned along the elevator shaft, each with a unique signature, allowing for precise radar-based distance measurements by selecting an optimal target reflector based on empirical height measurements and frequency spectrum analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If radar output power is increased to improve signal strength for long-distance measurement, then measurement range is improved, but regulatory constraints and safety requirements are violated
Solution Approach 1:
The elevator shaft is divided into multiple measurement zones, each with its own radar reflector positioned at specific heights. The system segments the long-distance measurement problem into multiple shorter-distance measurements, allowing each zone to operate within regulatory power limits while collectively covering the entire shaft height.
Solution Approach 2:
Radar reflectors are introduced as intermediary elements between the radar transceiver and the distant target. These reflectors amplify and redirect radar signals back to the transceiver, enabling long-distance measurement without increasing the transceiver's output power, thus maintaining regulatory compliance.
2Device complexity
If a single radar reflector is used for the entire shaft height, then device complexity is reduced, but measurement precision deteriorates due to signal attenuation over long distances
Solution Approach 1:
Multiple radar reflectors are distributed at different heights along the elevator shaft, creating multiple measurement zones. Each reflector provides accurate measurements for its specific zone, and the system selects the appropriate reflector based on the elevator car's current position, ensuring high measurement precision throughout the entire shaft height.
Solution Approach 2:
Instead of using a single reflector for the entire shaft, the system uses multiple reflectors that collectively provide coverage beyond what a single reflector could achieve. Each reflector is positioned to optimize measurement precision for its specific zone, ensuring accurate positioning throughout the full shaft height.
3Measurement precision
If radar reflectors are positioned close together to improve measurement precision, then positioning accuracy is improved, but the number of reflectors increases leading to higher system complexity
Solution Approach 1:
The system uses a moderate number of reflectors positioned at intervals that provide sufficient measurement precision without creating excessive system complexity. Each reflector covers a specific height range, and the system selects the appropriate reflector based on the elevator car's position, achieving good precision with a manageable number of components.
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
Accurately determines the position of an elevator car within an elevator shaft with an error of less than 10 millimeters, satisfying industry standards and reducing noise and interference effects.
Implementation Method 1
a radar-based distance measurement system used for detecting and measuring reflected radar signals from a plurality of radar reflectors
Implementation Method 2
detecting and measuring reflected radar signals from a plurality of radar reflectors
Implementation Method 3
at least one of the plurality of radar reflectors is a pyramidal frustum reflector configured to directly reflector radar signals originating from the dynamically-positioned radar transceiver back to the dynamically-positioned radar transceiver
Data Source
AI summary
Various embodiments are directed to determining an elevator car position within an elevator shaft using radar-based distance measurements and a plurality of radar reflectors positioned along the elevator shaft. In one aspect, an example method is provided. The method includes associating a height segment of the elevator shaft with each of the plurality of radar reflectors. The method further includes selecting a target reflector from the plurality of radar reflectors based at least in part on an initial height of the elevator car being within a height segment associated with the target reflector. The method further includes determining an inferred position of the elevator car within the elevator shaft based at least in part on determining a radar-based distance measurement to the target reflector. The radar reflectors may be positioned such that at least one radar reflector is optimally detectable by a dynamically-positioned radar transceiver of the elevator car.