3D Wireless Optical Positioning Using LED and Photodetectors
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Solution Overview
Problem
Current indoor visible light positioning methods are limited in achieving accurate 3D positioning and orientation due to the need for extensive parameter measurement, poor portability, and the inability to determine the actual orientation of the receiving terminal, especially in scenarios with a reduced number of LEDs or when dealing with 2D plane information.
Innovation Solution
A 3D wireless optical positioning method using LED lamps on the ceiling and a receiver with two photodetectors on the same plane, employing the TOA principle to calculate distances and orientation, allowing for accurate 3D positioning and orientation with a reduced number of optical transmitters, and enabling illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional geometric measurement method is used with at least three LED light sources, then trilateration or triangulation can be realized, but the use of positioning solutions is limited in scenarios with insufficient number of LEDs
Solution Approach 1:
The patent transitions from 2D positioning to 3D positioning by introducing vertical height information (z-coordinate) as an additional dimension. This is achieved by using two photodetectors at different vertical positions to capture light signals, enabling the calculation of three-dimensional coordinates (x, y, z) of the receiving terminal, thereby resolving the limitation of insufficient LEDs through dimensional expansion
Solution Approach 2:
The receiving terminal is segmented into two separate photodetectors positioned at different locations, with each photodetector independently receiving light signals from LED sources. This segmentation allows the system to obtain multiple independent measurement equations, enabling accurate positioning even with reduced number of LEDs by creating redundant measurement paths
2Ease of manufacture
If image sensor method is used to deal with light source projection, then 2D positioning can be realized, but the height of the receiving terminal cannot be calculated directly
Solution Approach 1:
The patent introduces an intermediary computational model based on time-of-flight measurements and geometric relationships. Instead of directly processing image sensor projections, the system uses flight time data from multiple photodetectors as intermediaries to calculate three-dimensional position coordinates, thereby enabling height calculation without complex image processing while maintaining implementation simplicity
Solution Approach 2:
The patent replaces the mechanical/optical image projection system with a time-based measurement system. Instead of using image sensors to capture spatial projections, the system uses photodetectors to measure the flight time of light signals, substituting geometric projection mechanics with temporal measurement, which directly provides three-dimensional position information including height
3Adaptability or versatility
If scenario analysis method is used, then positioning can be adapted to specific environments, but the parameter measurement process requires a great amount of work and poor portability
Solution Approach 1:
The patent implements a self-calibrating system where the positioning algorithm automatically adapts to different environments using the measured flight time data from photodetectors. The system performs self-service by computing position coordinates directly from raw measurements without requiring manual environmental parameter measurement or calibration, thereby reducing measurement time while maintaining environmental adaptability through automated computational adjustment
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 method simplifies deployment, improves portability, and achieves accurate indoor 3D positioning and orientation without additional devices, demonstrating good extensibility and stability in various indoor scenarios.
Implementation Method 1
through the TOA (Time of Arrival) principle, measuring the time required for the optical signal to be transmitted from the first LED lamp and the second LED lamp to and received by the first photodetector and the second photodetector respectively
Implementation Method 2
a first photodetector and a second photodetector with a coordinate of ({circumflex over (x)}r1, ŷr1, {circumflex over (z)}r1) and ({circumflex over (x)}r2, ŷr2, {circumflex over (z)}r2) respectively are arranged on the receiver, the distance between the first photodetector and the second photodetector is defined as l
Data Source
AI summary
The present invention provides a 3D wireless optical positioning method and system, including the steps of: arranging two LED lamps on the ceiling to transmit optical information and provide illumination; arranging a receiver including two photodetectors in a receiving plane; calculating the distance between the LED lamps and the photodetectors respectively through the TOA (Time of Arrival) method; and finally determining the actual position and orientation angle of the receiver based on the geometrical relationship between the LED lamps and the photodetectors in the XYZ coordinate system, the two photodetectors having a distance determined as l therebetween and being situated in the same receiving plane, the receiver being situated below the two LED lamps, the range where the receiver is to be positioned being on any side of the plane consisting of the two LED lamps and the origin.