Resolving Magnetic Dipole Ambiguity in Position Tracking
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Solution Overview
Problem
Magnetic position tracking systems face ambiguity in calculating relative coordinates when using dipole fields, resulting in multiple potential coordinates that may correspond to the correct location, leading to inaccurate measurements.
Innovation Solution
The system employs first and second field generators at different locations to generate magnetic fields, with position sensors measuring these fields, and utilizes a-priori knowledge about the position of one sensor relative to a field generator to resolve the ambiguity by comparing potential coordinates from both measurements and invalidating those not consistent with the a-priori information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a dipole magnetic field is used for position tracking, then the system can operate with simpler field generation, but the relative coordinate calculation becomes ambiguous with multiple potential coordinates
Solution Approach 1:
The system segments the field generation into multiple independent field generators (first and second field generators at different locations) rather than using a single dipole field source. This segmentation allows the system to maintain operational simplicity while resolving the coordinate ambiguity by providing multiple independent measurements that can be cross-referenced to determine the correct relative coordinate.
2Measurement precision
If multiple field generators are used to resolve coordinate ambiguity, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The multiple field generators serve multiple functions: they generate magnetic fields for position tracking, provide redundant measurements for ambiguity resolution, and enable cross-validation of coordinate calculations. This multi-functionality justifies the increased device complexity by delivering superior measurement precision and reliability.
Solution Approach 2:
The system uses feedback by comparing potential relative coordinates derived from different field generator combinations. The a-priori positional information serves as a reference against which calculated coordinates are validated, creating a feedback loop that eliminates ambiguous solutions and confirms the correct relative coordinate.
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 ensures unambiguous position tracking by eliminating incorrect coordinate options, providing a single, accurate relative coordinate between objects, thus minimizing tissue damage during medical procedures.
Implementation Method 1
first and second field generators at different locations are used to generate respective first and second magnetic fields in the vicinity of the two objects
Implementation Method 2
Two position sensors respectively associated with the two objects measure the first and second fields
Data Source
AI summary
A method for position tracking includes using first and second field generators located at respective different first and second locations to generate respective first and second magnetic fields in a vicinity of first and second objects. The first and second fields are measured using first and second position sensors respectively associated with the first and second objects. First and second potential relative coordinates of the first object relative to the second object are calculated responsively to the first and second magnetic field. The potential relative coordinates are processed in order to determine a correct relative coordinate of the first object relative to the second object.