UWB Beacon Synchronization for Accurate Indoor Positioning
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Solution Overview
Problem
Existing positioning systems face inaccuracies and uncontrollable errors in indoor and dense industrial environments due to multipath propagation and attenuation of RF signals, requiring a large number of anchor stations for line-of-sight coverage, which increases installation costs and power consumption.
Innovation Solution
A positioning system utilizing an ultrawide band two-way ranging method with synchronized active tags and beacons, employing a common time base and TDMA for efficient distance calculations and reduced crosstalk, allowing for accurate location determination using a network of beacons and tags, with battery-powered operation and low power communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a larger number of anchor stations are deployed to ensure line-of-sight coverage, then positioning accuracy is improved, but installation cost and device complexity increase
Solution Approach 1:
The system dynamically adjusts the number and distribution of anchor stations based on real-time signal quality assessments. When multipath conditions are detected, the system can temporarily increase anchor station usage for specific measurements while maintaining overall system configuration, allowing flexibility without permanent over-deployment
Solution Approach 2:
The patent changes the operational parameters of anchor stations by enabling them to function in multiple modes (e.g., full ranging mode vs. reduced functionality mode) depending on signal conditions. This allows the same physical infrastructure to provide varying levels of service without requiring proportional increases in hardware
2Reliability
If more anchor stations are installed to overcome signal attenuation and reflections, then positioning reliability is improved, but power consumption increases
Solution Approach 1:
Anchor stations transmit synchronization signals and ranging requests in periodic intervals rather than continuously. This allows the system to maintain timing information and enable ranging operations while keeping power consumption at acceptable levels for battery-powered portable devices
Solution Approach 2:
The system dynamically adjusts anchor station activity levels based on current positioning needs and signal conditions. When multiple anchor stations are required for reliability, they can coordinate to reduce individual transmission frequencies while maintaining collective coverage, optimizing the balance between reliability and power consumption
3Measurement precision
If continuous synchronization is maintained between all tags and beacons, then measurement accuracy is improved, but system complexity and processing requirements increase
Solution Approach 1:
The system uses periodic synchronization broadcasts from anchor stations rather than continuous synchronization maintenance. Tags synchronize to the periodic beacon signals and maintain timing information locally, reducing the computational burden while preserving measurement accuracy through consistent time references
Solution Approach 2:
The patent introduces a centralized or distributed coordination mechanism that acts as an intermediary to manage synchronization across the network. This mediator handles the complexity of coordinating multiple tags and beacons, allowing individual devices to operate simpler synchronization protocols while maintaining overall system accuracy
4Measurement precision
If ultrawide band signals are used for two-way ranging, then distance measurement accuracy is improved, but susceptibility to multipath errors increases
Solution Approach 1:
The system converts the harmful multipath reflections into useful information by measuring the time of flight for direct signals and using signal strength and arrival time patterns to identify and exclude reflected paths. The patent processes multiple signal copies to distinguish direct-line-of-sight signals from reflections, turning the multipath problem into an opportunity for improved signal selection
Solution Approach 2:
The system incorporates feedback mechanisms where tags and beacons continuously assess signal quality and adjust their ranging operations accordingly. When multipath conditions are detected through signal analysis, the system can request retransmissions, switch to alternative anchor stations, or modify measurement parameters to obtain cleaner signals
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 achieves accurate positioning with reduced power consumption and installation costs by minimizing multipath errors and crosstalk, enabling efficient coordination of measurements and varying update rates for different tags.
Implementation Method 1
A positioning system utilizing an ultrawide band two-way ranging method with synchronized active tags and beacons
Implementation Method 2
Time of flight (ToF) is the amount of time a signal takes to propagate from transmitter to receiver. Because the signal propagation rate is constant and known, the travel time of a signal can be used directly to calculate distance.
Data Source
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AI summary
An ultrawide band two-way ranging based positioning system (600) includes a number of active tags (606) each having a position, and a number of beacons (604) configured for location of a position of a tag (606) of the plurality of active tags. The active tags (606) and the beacons (604) are synchronized continuously to a common time base.