3D RFID Tag Positioning via Angle and Signal Strength
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Solution Overview
Problem
Conventional RFID tag positioning systems face challenges in accurately estimating three-dimensional positions, especially at larger communication distances, and require numerous samples and time, limiting their effectiveness.
Innovation Solution
A method involving a mobile object with a radio receiver that determines the three-dimensional position of an RFID tag by detecting receiving states through horizontal and vertical angle calculations and distance measurements, using a robot to adjust its position and orientation to receive radio signals from the tag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional RFID positioning method is used, then the system can detect the presence of an RFID tag, but the position estimation accuracy deteriorates when the tag is placed relatively far away
Solution Approach 1:
The patent transitions from two-dimensional position estimation to three-dimensional position estimation by incorporating vertical angle measurements. The mobile object captures images at multiple vertical angles and uses these to calculate the three-dimensional position coordinates (x, y, z) of the RFID tag, thereby improving accuracy at larger communication distances
Solution Approach 2:
The patent employs a mobile object that can dynamically change its position and orientation to capture images of the RFID tag from multiple viewpoints. The mobile object moves to different locations and adjusts its imaging angle, enabling it to gather sufficient data for accurate three-dimensional position estimation even when the tag is far away
2Measurement precision
If the RFID antenna is moved to multiple positions for position estimation, then the position accuracy may improve, but the time required for position estimation increases significantly
Solution Approach 1:
The patent uses periodic action by capturing images at multiple predetermined vertical angles in a systematic sequence. The mobile object captures images at angles such as -30°, -15°, 0°, +15°, and +30° in a periodic pattern, which allows efficient data collection for three-dimensional position estimation without requiring excessive time
Solution Approach 2:
The patent performs preliminary action by pre-establishing the relationship between image capture positions, vertical angles, and RFID tag positions through calibration. The system pre-stores correspondence data between mobile object positions, imaging angles, and tag position coordinates, enabling rapid position estimation during actual operation without time-consuming real-time calculations
3Productivity
If two-dimensional position estimation is performed, then the estimation process is simpler and faster, but the position accuracy deteriorates when expanded to three-dimensional space
Solution Approach 1:
The patent extends two-dimensional position estimation to three-dimensional space by incorporating the vertical angle dimension. The system captures images at multiple vertical angles and uses these to calculate the third dimension (height/z-coordinate) of the RFID tag position, achieving accurate three-dimensional localization while maintaining operational efficiency
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
Enables accurate and quick three-dimensional position estimation of RFID tags, improving accuracy and reducing the time and samples required compared to conventional methods.
Implementation Method 1
a radio receiver receives a radio signal from the radio transmitter
Data Source
AI summary
A method for determining a three-dimensional position of an RFID tag includes moving a mobile object carrying an RFID antenna in a workplace to a first position where the RFID antenna receives a radio signal from the RFID tag. A horizontal angle and a vertical angle are determined from the RFID antenna to the RFID tag based on the feasibility of communication between the RFID antenna and the RFID tag as the RFID antenna is turned or moved in a horizontal direction and a vertical direction, respectively, at the first position. A distance from the RFID antenna to the RFID tag is determined based on the power of the signal received from the RFID tag. A three-dimensional position of the RFID tag is determined by vector calculation using the horizontal angle, the vertical angle, and the distance.