UWB Access Control Module for Front-to-Back Direction Detection
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Solution Overview
Problem
The phase difference of arrival (PDoA) method in ultra-wideband (UWB) communication-based positioning faces a front-to-back ambiguity issue when applied to fixed terminals like access authentication devices, leading to difficulties in determining the direction of user terminals.
Innovation Solution
An access control device with a communication module and processors that utilize UWB communication to receive signals from user terminals, analyzing changes in phase angles to determine the direction of the terminals based on the substrate and ground configuration, effectively resolving front-to-back ambiguity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the PDoA method is applied to fixed terminals like access authentication devices, then positioning capability is achieved, but front-to-back ambiguity occurs making direction determination impossible
Solution Approach 1:
The patent transitions from two-dimensional phase angle measurement to three-dimensional spatial discrimination by utilizing the physical structure of substrate and ground in different directions. By measuring phase angles in multiple spatial dimensions (first direction from substrate, second direction from ground), the system resolves the front-to-back ambiguity that plagues conventional single-plane PDoA methods.
Solution Approach 2:
The patent introduces substrate and ground as intermediary reference structures that mediate between the antenna and the user terminal. These intermediaries create distinct signal paths with different phase characteristics for terminals in different directions, enabling the system to distinguish between front and back positions that would otherwise be ambiguous.
2Device complexity
If conventional antenna configuration is used, then device simplicity is maintained, but direction discrimination capability is lost
Solution Approach 1:
The patent introduces asymmetric structural elements (substrate and ground) positioned in specific directions relative to the antenna. This asymmetric configuration creates non-reciprocal phase shifts for signals arriving from different directions, enabling direction discrimination while maintaining relative structural simplicity. The asymmetry is minimal yet sufficient to break the front-to-back symmetry of conventional omnidirectional antennas.
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
The solution accurately distinguishes between terminals positioned in different directions by exploiting differences in signal interference patterns, thereby overcoming the ambiguity and enhancing the accuracy of user authentication and access control.
Implementation Method 1
The PDoA method refers to a method for tracing a plurality of tags through one anchor, and is increasingly used in recent years. However, the PDoA method is optimized for portable terminals like smartphones, and, when the PDoA method is applied to a fixed terminal such as an access authentication device, there may be a problem of front-to-back ambiguity.
Implementation Method 2
The TDoA method refers to a method for tracing a plurality of tags through a plurality of anchors.
Implementation Method 3
The solution accurately distinguishes between terminals positioned in different directions by exploiting differences in signal interference patterns, thereby overcoming the ambiguity and enhancing the accuracy of user authentication and access control.
Data Source
AI summary
An access control device according to an embodiment includes: a communication module configured to perform communication by using a UWB communication protocol and one or more processors, and the communication module includes: a substrate, an antenna disposed on a first surface of the substrate, and a ground disposed on a second surface which is opposite to the first surface of the substrate, and the one or more processors are configured to: receive a signal from a user terminal through the communication module; and determine whether the user terminal is positioned in a first direction or second direction, based on a change in a phase angle of the signal received from the user terminal when a direction from the substrate to the antenna is the first direction and a direction from the substrate to the ground is the second direction.