Wheel-Based Dead Reckoning Navigation for Cart Position Tracking
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Solution Overview
Problem
Existing methods for tracking the position of wheeled objects in large areas are either expensive, require extensive infrastructure, or are prone to errors due to signal interference and blockages, such as GPS and RF tag systems.
Innovation Solution
A navigation system using dead reckoning methods that estimates an object's position by measuring wheel rotation and heading, with error correction and position reset procedures, and can communicate with external markers and RF transmitters to prevent theft by activating anti-theft systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS or RF tag systems are used to track wheeled objects, then position information can be obtained, but the system becomes expensive and requires extensive infrastructure installation
Solution Approach 1:
The patent replaces electronic/GPS-based position determination systems with a mechanical dead reckoning system that uses wheel rotation sensors and heading sensors to calculate position. This substitution eliminates the need for extensive GPS receiver infrastructure or RF tag systems, reducing both cost and complexity while maintaining position tracking capability
Solution Approach 2:
The wheeled object determines its own position autonomously using onboard sensors (wheel rotation sensor and heading sensor) without requiring external infrastructure. The object serves itself by calculating its position through dead reckoning based on its own motion parameters, eliminating dependency on external GPS satellites or RF infrastructure
2Reliability
If GPS signal is used for position tracking, then location can be determined, but the system fails when GPS signal is blocked or satellite visibility is interrupted
Solution Approach 1:
The patent converts the limitation of no external signal reference into an advantage by using the object's own motion characteristics (wheel rotation and heading) as the primary reference. This self-contained approach transforms the absence of external GPS signals from a harmful factor into a beneficial independence from external signal blockage
Solution Approach 2:
Instead of relying on external signals (GPS satellites) to determine position, the system inverts the approach by using internal motion sensors to calculate position through dead reckoning. This inversion makes the system immune to external signal blockage while maintaining continuous position tracking
3Device complexity
If dead reckoning method is used to estimate position, then cost and infrastructure are reduced, but navigational error accumulates over time
Solution Approach 1:
The patent implements feedback through periodic position resets when the wheeled object returns to known reference locations. This feedback mechanism corrects accumulated dead reckoning errors by re-synchronizing the calculated position with actual known positions, maintaining long-term accuracy without requiring continuous external infrastructure
Solution Approach 2:
The system performs periodic position resets at known reference points along the travel path. This periodic correction action prevents error accumulation by regularly recalibrating the dead reckoning calculation against known positions, maintaining measurement precision over extended periods
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
Provides a reliable, cost-effective, and autonomous means to track wheeled objects, reducing errors and preventing unauthorized movement by accurately determining positions and triggering anti-theft mechanisms.
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
AI summary
A navigation system uses a dead reckoning method to estimate an object's present position relative to one or more prior positions. In some embodiments, 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. Some or all of the components of the navigation system may be disposed within a wheel, such as a wheel of a shopping cart.