Dual Antenna Base Station for RFID Localization
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Solution Overview
Problem
Existing RFID base stations struggle to precisely determine the location of RFID tags due to the lack of directional antennas, leading to difficulties in distinguishing signals from adjacent rooms or floors, and the use of IR technology is not effective without a clear line of sight.
Innovation Solution
Employing a base station with an antenna assembly that provides two non-overlapping directional signals, allowing for the determination of the signal direction from two sets of directions, and using multiple base stations to triangulate the tag's location within a building.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional RFID base stations use omnidirectional antennas, then they can receive signals from all directions, but they cannot determine the direction of incoming signals
Solution Approach 1:
The antenna system is segmented into multiple directional antenna elements, each sensitive to signals from specific directions. By dividing the omnidirectional reception capability into discrete directional segments, the system can determine signal origin while maintaining comprehensive coverage
Solution Approach 2:
The patent employs asymmetric antenna radiation patterns where each antenna element has a specific directional sensitivity profile. This asymmetry in signal reception characteristics enables direction determination by comparing relative signal strengths across multiple asymmetric antenna patterns
2Loss of energy
If base stations use non-directional antennas in buildings with transparent walls, then signals can pass through walls freely, but the base station cannot distinguish between signals from adjacent rooms or floors
Solution Approach 1:
The antenna array is segmented into multiple elements with distinct directional patterns, allowing the system to segment the spatial reception space. This enables the base station to identify which specific room or floor a signal originates from, even when walls are transparent to RF radiation
Solution Approach 2:
The patent introduces directional antenna patterns as an intermediary mechanism between the RF signal and the base station processor. These antenna patterns act as spatial filters that mediate the reception process, providing directional information that would otherwise be lost in omnidirectional reception
3Measurement precision
If triangulation is performed using relative transmitted powers without known absolute strength, then tag location can be approximated, but the calculations become quite difficult requiring numerical methods
Solution Approach 1:
The patent transitions from power-based triangulation (one-dimensional power comparison) to direction-based localization (adding angular dimension). By measuring signal strength across multiple directional antenna elements, the system creates a spatial signature that directly indicates direction, simplifying the mathematical problem from complex numerical triangulation to more straightforward angular comparison
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 precise localization of RFID tags within rooms by distinguishing between signal directions and using triangulation with multiple base stations, improving accuracy and reducing ambiguity in environments with non-directional RF radiation.
Implementation Method 1
an antenna assembly that provides two output signals, with one signal corresponding to the strength of signal received from substantially a first set of directions, and the other signal corresponding to the strength of signal received from substantially another set of directions
Data Source
AI summary
A base station that uses an antenna assembly and associated signal processing where the antenna assembly includes at least one directional antenna, developing information from which a determination is made regarding the direction from which a received signal is coming. By employing a plurality of such base stations the location of a transmitting tag is ascertained.