Magnetic Tracking System Synchronization via Time Slot Assignment
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Solution Overview
Problem
Current magnetic tracking systems lack the ability to autonomously detect the presence of other AC trackers in their proximity and cannot operate in close physical proximity without interference.
Innovation Solution
A system where one magnetic tracking system assumes the role of 'master' upon boot-up, assigning time slots and identification codes to its own and other systems' transmitting antennas, allowing them to operate without interference using a separate synchronization channel like infrared or radio frequency links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple magnetic tracking systems operate in the same physical space, then the system can support multiple users and applications, but interference between systems occurs and reliable operation cannot be maintained
Solution Approach 1:
The patent divides the continuous time domain into discrete time slots, assigning each magnetic tracking system a specific time slot for transmission. This temporal segmentation allows multiple systems to share the same physical space without interference, as each system transmits sequentially rather than simultaneously. The master system coordinates these time slots to ensure no overlap occurs between different tracking systems.
Solution Approach 2:
The patent implements periodic time-based transmission cycles where each magnetic tracking system transmits during its assigned time slot and remains silent during other slots. This periodic action pattern ensures that multiple systems can operate in the same space by repeating the cycle of transmit-listen-swap, preventing continuous interference while maintaining regular operation for all users.
2Speed
If magnetic tracking systems transmit continuously, then position and orientation data can be updated frequently, but other systems in proximity cannot operate without interference
Solution Approach 1:
The system uses periodic time-slot-based transmission where each tracking system transmits at regular intervals during its assigned slot rather than continuously. This maintains acceptable update rates for position and orientation data while preventing continuous interference with other systems, achieving a balance between data freshness and multi-system compatibility.
Solution Approach 2:
The master system pre-assigns time slots to each tracking system before operation begins. This preliminary arrangement of transmission schedules allows all systems to know in advance when they should transmit and when they should listen, enabling coordinated operation that maintains data update rates without causing interference.
3Device complexity
If a single frequency is used for magnetic field transmission, then the system is simpler to implement, but multiple systems cannot share the same frequency without interference
Solution Approach 1:
Instead of adding frequency diversity (another dimension of signal differentiation), the patent transitions from frequency-based to time-based differentiation. By moving the discrimination dimension from frequency domain to time domain, the system maintains simple single-frequency transmission while enabling multiple systems to operate through temporal separation, avoiding the complexity of frequency management.
Solution Approach 2:
The patent segments the transmission opportunity in time rather than dividing the frequency spectrum. Each tracking system is assigned a specific time segment (time slot) for transmission using the same frequency, which simplifies the device complexity compared to frequency management while still supporting multiple systems through temporal segmentation.
4Extent of automation
If magnetic tracking systems autonomously detect other systems, then coordination between systems can be achieved, but the detection mechanism adds system complexity
Solution Approach 1:
The master system performs the coordination function by actively assigning time slots to other tracking systems rather than requiring each system to autonomously detect and negotiate with others. This self-service approach by the master system reduces the detection and coordination complexity that would otherwise be distributed across all systems, achieving automated coordination with simpler individual device requirements.
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
Enables multiple magnetic tracking systems to operate in close proximity without interference, allowing multiple users to track their movements in the same physical environment while maintaining continuous and accurate position and orientation data.
Implementation Method 1
using a separate synchronization channel like infrared or radio frequency links
Implementation Method 2
a transmitter comprising a plurality of radiating antennas, located at a source to provide a plurality of magnetic fields spanning three dimensional space
Data Source
AI summary
A method and apparatus is disclosed for allowing a magnetic tracking system to detect, and operate in close proximity in the same physical environment with, additional magnetic tracking systems. The first user's magnetic tracking system that becomes active in the physical space becomes the master system, and assigns time slots for its own transmitting antennas to generate the magnetic field which is used to determine the position and orientation of the user's limbs relative to the user's head. The master system also determines when other magnetic tracking systems become active in the physical space and assigns to those systems identification codes and time slots for their transmitting antennas to generate a magnetic field so that the position and orientation of the user's hands relative to the user's head for each of those systems may be determined. By requiring each magnetic tracking system to operate in different time slots, there is no interference between the systems.