Wheel-Integrated Dead Reckoning Navigation for Cart Theft Control
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Solution Overview
Problem
Existing navigation systems for wheeled objects in large tracking areas face challenges such as high installation costs, interference from structural attenuations, and satellite signal blockages, making it difficult to accurately track and prevent theft of objects like shopping carts.
Innovation Solution
A navigation system using dead reckoning methods, combined with magnetic sensors to determine heading and wheel rotation, which activates an anti-theft mechanism if the object exits a designated area, allowing for autonomous position estimation and reduced error accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RF tag and receiver systems are used to track objects in large areas, then position tracking capability is improved, but system cost and complexity increase due to requiring many receivers
Solution Approach 1:
The patent replaces the complex RF tag and receiver system with a mechanical dead reckoning system using magnetic sensors and wheel rotation sensors. This substitution eliminates the need for multiple receivers throughout the tracking area, reducing system cost and complexity while maintaining position tracking capability.
Solution Approach 2:
The navigation system is self-contained within the wheeled object, using its own wheel rotation data and magnetic heading information to determine position. This self-service approach eliminates dependence on external receiver infrastructure, reducing both system cost and complexity.
2Measurement precision
If GPS systems are used to determine position, then position tracking is improved, but reliability deteriorates when satellite signals are blocked or visibility is interrupted
Solution Approach 1:
The patent replaces GPS satellite-based positioning with a terrestrial dead reckoning system using magnetic sensors and wheel rotation sensors. This mechanical substitution ensures reliable position determination independent of satellite signal availability, eliminating reliability issues during signal blockage.
3Device complexity
If dead reckoning navigation is used in wheeled objects, then system cost is reduced, but measurement precision deteriorates due to accumulated error over time
Solution Approach 1:
The patent implements error correction procedures that use feedback from magnetic sensors to detect and correct drift in the dead reckoning position estimates. This feedback mechanism maintains measurement precision over extended periods while keeping the system cost-effective.
Solution Approach 2:
The system dynamically adjusts its navigation parameters by switching between dead reckoning mode and magnetic field-based position reset mode. This parameter change strategy corrects accumulated errors without requiring expensive additional hardware, maintaining both cost-effectiveness and accuracy.
4Reliability
If magnetic sensors and wheel rotation sensors are combined for dead reckoning, then position estimation reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the magnetic sensor and wheel rotation sensor into an integrated dead reckoning navigation system with unified processing. This merging approach improves position estimation reliability by combining complementary sensor data while managing overall device complexity through integrated design.
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 system provides a reliable, cost-effective means to track and prevent theft of wheeled objects by accurately determining their position and activating anti-theft measures, reducing errors and installation complexities.
Implementation Method 1
the heading is determined with reference to the Earth's magnetic field by disposing magnetic sensors in or on the object
Data Source
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AI summary
A navigation system uses a dead reckoning method to estimate an object's present position relative to one or more prior positions. The dead reckoning method determines a change in position from the object's heading and speed during an elapsed time interval. In embodiments suitable for use with wheeled objects, the dead reckoning method determines the change in position by measuring the heading and the amount of wheel rotation. The heading is determined with reference to the Earth's magnetic field by disposing magnetic sensors in or in the object. Error correction and position reset procedures may be implemented to reduce accumulated navigational error. In preferred embodiments, some or all of the navigation system is disposed within a wheel of the object. The navigation system determines whether the object has exited a confinement area and activates an anti-theft system such as an alarm or wheel locking mechanism.