RFID Tag Distance Measurement Using Replica Path Taps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current RFID tag distance measurement technologies lack accuracy and efficiency in determining the range to RFID tags, especially in environments where signal propagation delays and variations in medium affect the reliability of distance calculations.
Innovation Solution
The system employs a replica path with taps at specific intervals to compare the signal travel time with the RFID tag's response, using comparators and potentially incorporating analog-to-digital converters to enhance measurement resolution, and can adjust propagation delays to simulate the RFID tag's behavior, allowing for precise distance determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional RFID distance measurement methods are used, then the system is simple to operate, but measurement precision is poor due to signal propagation delays and medium variations
Solution Approach 1:
The patent creates a replica path that copies the signal transmission characteristics of the actual RFID communication path. By generating a replica signal that travels through an identical path and experiences the same propagation delays and medium variations, the system can compare the replica signal with the actual received signal to accurately determine distance measurements, thereby resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The system performs preliminary actions by pre-establishing the replica path and generating the replica signal before the actual measurement is needed. The replica signal is prepared in advance with known characteristics, allowing the system to compensate for propagation delays and medium variations without adding complexity to the real-time measurement process
2Measurement precision
If signal propagation delays are not accounted for, then the device complexity is low, but measurement precision deteriorates due to uncorrected timing errors
Solution Approach 1:
The patent implements feedback by continuously comparing the replica signal with the actual received signal from the RFID tag. This comparison provides feedback information about propagation delays and medium variations, which is then used to adjust and refine the distance measurement calculations, achieving high precision without excessive processing complexity
Solution Approach 2:
The replica signal acts as an intermediary that mediates between the transmitted signal and the received signal. By introducing this intermediate reference signal that experiences identical propagation conditions, the system can isolate and measure propagation delays without requiring complex direct measurement methods
3Reliability
If the measurement system does not adapt to medium variations, then the device complexity remains low, but reliability decreases in different environments
Solution Approach 1:
The patent achieves universality by designing a measurement system that can operate reliably across different environments and medium conditions. The replica path approach is universally applicable regardless of the transmission medium, as the replica signal experiences the same conditions as the actual signal, making the system adaptable to various environments without requiring environment-specific configurations
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 provides accurate and reliable distance measurements to RFID tags by accounting for signal propagation delays and medium variations, improving measurement resolution and adaptability across different environments.
Implementation Method 1
Radio frequency Identification (RFID) tags use radio-frequency electromagnetic fields to transfer data from a tag attached to an object
Implementation Method 2
One embodiment utilizes a measuring device that sends a signal down two paths. The first path includes a wireless transmission to an RFID tag and the second path is a replica. A comparison is then performed between the replica signal traveling a known distance with an incoming signal received from the RFID tag
Data Source
AI summary
A radio frequency identification (RFID) tag distance measuring system and method is disclosed. One example includes a first replica path that receives a signal that is simultaneously transmitted to an RFID tag. The first replica path includes a plurality of taps at known distances along the first replica path. Each of the plurality of taps has a first tap input coupled with the first replica path. In addition, an RFID signal receiver receives a return signal from the RFID tag and provides the return signal along a measurement input, wherein each of the plurality of taps have a second tap input coupled with the measurement path. A distance determiner detects at least the first of the plurality of taps to have an output and determine a distance measurement to the RFID tag based thereon.