Localization and Posture Recognition via Magneto-Inductive and Relay-Aided Sensor Networks
Henry Ruben Lucas Schulten
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Henry Ruben Lucas Schulten, Localization and Posture Recognition via Magneto-Inductive and Relay-Aided Sensor Networks (2022), Logos Verlag, Berlin, ISBN: 9783832584177
Beschreibung / Abstract
Body-centric wireless sensor networks are expected to enable future technologies such as medical in-body micro robots or unobtrusive smart textiles. These technologies may advance personalized healthcare as they allow for tasks such as minimally invasive surgery, in-body diagnosis, and continuous activity recognition. However, the localization of individual sensor nodes within such networks or the determination of the entire network topology still pose challenges that need to be solved. This work provides both theoretic and simulative insights to enable the required sub-millimeter localization accuracy of such sensors using magneto-inductive networks. It identifies inherent localization issues such as the asymmetry of the position estimation in magneto-inductive networks and outlines how such issues may be addressed by using passive relays or cooperation. It further proposes a novel approach to recognize the entire structure of a magneto-inductive network using simple impedance measurements and clusters of passive tags. This approach is evaluated extensively by simulation and experiment to demonstrate the feasibility of low-cost human body posture recognition.
Inhaltsverzeichnis
- BEGINN
- Abstract
- Kurzfassung
- Motivation and Contributions
- Wireless Technologies for Body-Centric Applications
- Localization in Sensor Networks
- Posture and Activity Recognition
- Contributions, Publications, and Structure
- Acknowledgments and Joint Work
- Coil Antennas and Magneto-Inductive Coupling
- Inductive Coupling and Limiting Assumptions
- Electrically Small and Thin-Wired Coils
- Inductive Coupling in a Network of Coil Antennas
- Fundamental Theory
- Circuit-Based Multiport Model
- Noise Model
- Matching, Equivalent Model, and Further Assumptions
- Parameter Estimation and Cramér-Rao Lower Bound
- Range Estimation and Localization
- Range Estimation for Active and Passive Agents
- Scaling Behavior for Practical Design Parameters
- Impact of Anchor Placement and Density
- Impact of Agent Placement
- Conclusions
- Passive Relays and Relay-Aided Localization
- Incorporation of Passive Relay Coils
- Localization Impact of Passive Relays for Selected Topologies
- Load Switching of Passive Relays
- Localization Performance for Random Relay Topologies
- Conclusions
- Cooperative Localization
- Weakly-Coupled Channel Gain and Noise Model
- Position Error Bounds
- Cooperative and Non-Cooperative Deployment Estimators
- Performance Evaluation for IoT Topologies
- Conclusions
- Topology Classification Using Purely Passive Tags
- Topology Classification System Concept
- General Design Challenges and Considerations
- Possible Use Cases for Topology Classification
- Simplified System Model
- Human Posture Recognition: A Case Study
- Body Models and Postures
- Noise Models
- Coil Types and Placement
- Data Set Generation and Classifiers
- Performance Evaluation
- Conclusions
- Posture Recognition Demonstrator
- Demonstrator and Measurement Setup
- Single-Frequency System
- Multi-Frequency System
- Conclusions
- Summary
- APPENDICES
- System Model Derivatives and Fisher Information
- Relay-Specific Derivatives
- Trace Maximization for Pairwise Distance Estimates
- Preliminary Measurements of an Anchor-Tag Coil Pair
- General Detuning Observations for an Anchor-Tag Pair
- Impact of Distorting Objects
- Noise Characterization
- Mathematical Notation and Operators
- List of Acronyms
- Bibliography