RFID Tag Signpost Transition Logic for Crane Tracking
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Solution Overview
Problem
RFID tags used for tracking containers can 'flip-flop' between recognizing two overlapping signposts, causing unreliable data transmission, and existing techniques do not effectively manage this issue during container movement by cranes, especially in environments where signpost signals collide or overlap.
Innovation Solution
The RFID tag employs a technique involving a timer and signpost code management to ensure a single transition between recognizing one signpost and another, ignoring alternating signals until it exits the overlap region, and the central system synchronizes signpost transmissions to prevent collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If RFID tags are used to track containers in overlapping signpost transmission fields, then container tracking coverage is improved, but the tags experience signal flip-flopping between signposts causing unreliable data transmission
Solution Approach 1:
The system performs preliminary synchronization of signpost transmissions before container tracking operations. The central controller coordinates signposts to transmit signals in alternating time slots, preventing overlapping transmissions that cause tag flip-flopping. This preliminary timing arrangement ensures reliable data transmission while maintaining broad coverage.
Solution Approach 2:
Signposts transmit signals in periodic alternating time slots rather than continuously overlapping. Each signpost transmits during its designated time window, creating a periodic pattern that eliminates signal collisions. This allows RFID tags to reliably receive and process signals without flip-flopping between competing transmissions.
2Area of stationary object
If multiple signposts are deployed to cover large areas, then tracking coverage is improved, but signal collisions occur in overlap regions causing tag recognition instability
Solution Approach 1:
The central controller pre-coordinates signpost transmission schedules to eliminate collisions in overlap regions. By establishing a synchronized timing pattern before operations begin, the system ensures that tags experience stable, non-conflicting signals even when multiple signposts are active in the coverage area.
Solution Approach 2:
The system dynamically assigns transmission time slots to different signposts based on their spatial locations and coverage areas. This dynamic time-division multiplexing allows the system to adapt to different container positions and maintain stable tag recognition across the entire tracking coverage area.
3Reliability
If signposts transmit continuously to maintain coverage, then tracking availability is improved, but energy consumption increases and signal collisions occur
Solution Approach 1:
Signposts transmit signals in periodic time slots rather than continuously. Each signpost activates only during its assigned transmission window, reducing overall energy consumption while maintaining continuous tracking coverage through coordinated alternating transmissions. This periodic operation eliminates signal collisions and reduces power usage.
Solution Approach 2:
The synchronized periodic transmission pattern ensures continuous tracking availability without requiring all signposts to transmit simultaneously. The coordinated timing maintains uninterrupted coverage while allowing individual signposts to remain inactive during their non-transmission slots, optimizing energy 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
This approach prevents repeated 'flip-flopping' of the RFID tag between signposts, ensuring stable and accurate tracking of containers during movement by ensuring a single transition and minimizing signal collisions, thereby enhancing tracking reliability.
Implementation Method 1
mount a radio frequency identification (RFID) tag on the container. The RFID tag can transmit wireless signals, and typically can also receive wireless signals
Data Source
AI summary
A tag can receive first and second wireless signals respectively defining first and second transmission fields that overlap. When the tag moves from the first field to the second field through the region of overlap, the apparatus transitions only once from recognizing the tag is in the first field to recognizing the tag is in the second field. According to another aspect, first and second signposts are supported at spaced locations in the region of a crane, and respectively transmit first and second wireless signals that are different, and that respectively define first and second fields of transmission. According to yet another aspect, a signpost transmits wireless signals having a transmission field, and a system senses positional information regarding a tag movable relative to the signpost, the system using the positional information to determine a location of the tag in relation to the transmission field.