Multipath UWB Tag Localization via Intermediate Relays
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Solution Overview
Problem
Existing tracking technologies face challenges in accurately locating target tags over long ranges due to increased ranging and localization errors, especially when the target tag is far from the computing device, leading to unreliable estimates and difficulties in implementing far-field applications such as vehicle location and parking management.
Innovation Solution
The use of wireless components in computing devices to broadcast encrypted data frames over Ultra-Wideband (UWB) signals to neighboring intermediate tags, which provide combined direct and indirect path responses to determine the target tag's distance and direction, leveraging the 'wisdom-of-crowds' concept to mitigate noise and improve accuracy through a loss-function algorithm that weights path parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If direct ranging measurements are used between computing device and target tag, then localization speed is improved, but measurement precision deteriorates when target tag is far from computing device
Solution Approach 1:
The patent introduces intermediate tags as mediators between the computing device and the target tag. When the target tag is out of direct range, the computing device communicates with intermediate tags that are within range, and these intermediaries relay positioning information. This allows the system to maintain localization functionality even when direct communication is not possible, effectively resolving the contradiction between speed and precision by providing alternative measurement paths.
Solution Approach 2:
The patent segments the direct ranging path into multiple indirect paths through intermediate tags. Instead of relying on a single direct measurement that fails at long ranges, the system divides the localization task into multiple smaller ranging measurements between neighboring devices. Each segment maintains sufficient signal strength for accurate measurement, and the results are combined to achieve overall target localization.
2Device complexity
If single-path ranging method is used, then device complexity is reduced, but reliability deteriorates due to noise and multipath errors
Solution Approach 1:
The patent merges multiple ranging paths (direct path and indirect paths through intermediate tags) to determine target tag location. By combining measurements from multiple paths, the system can mitigate the effects of noise and multipath errors that affect individual paths. The loss-function algorithm weights and combines these measurements to produce a more reliable location estimate than any single path could provide alone.
Solution Approach 2:
The patent implements a feedback mechanism where the system evaluates the quality of different ranging paths using a loss-function algorithm. Paths with better signal quality and lower estimated error receive higher weights in the final calculation. This feedback-driven weighting allows the system to dynamically adapt to changing environmental conditions and reliably select the most accurate measurement paths.
3Measurement precision
If multiple paths through intermediate tags are used, then measurement precision is improved by mitigating noise, but device complexity increases
Solution Approach 1:
The patent applies partial action by selectively using only those intermediate tags and paths that contribute meaningfully to localization accuracy. The loss-function algorithm evaluates multiple potential paths but only incorporates those that meet certain quality thresholds into the final calculation. This avoids the excessive complexity of processing all possible paths while still capturing the benefits of multi-path diversity for noise mitigation.
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 enhances the accuracy of target tag localization by combining noise profiles from multiple paths, providing improved range and direction estimates even when the target tag is not directly reachable, thus overcoming the limitations of single-path methods and enhancing the reliability of long-range sensing applications.
Implementation Method 1
The wireless transceiver may then broadcast an encrypted data frame over a wireless signal (e.g., Ultra-Wideband ®
Implementation Method 2
The computing device may determine the initial target tag distance, if reachable, and each first-hop distance, corresponding to the distance from the computing device to at least some of the intermediate tags, based on a round-trip-time algorithm that determines round-trip-times (RTT) of the wireless signal
Data Source
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AI summary
A computing device is described that includes one or more processors, a wireless transceiver that broadcasts a message over a wireless signal to locate a target tag, and a locator application. The locator application is operable by the one or more processors to receive, in response to the broadcast message, a plurality of intermediate responses from one or more intermediate tags, determine a first-hop direction and a first-hop distance to at least one first-hop intermediate tag based on the plurality of intermediate responses, and determine a target tag distance and a target tag direction from the computing device to the target tag based on each first-hop direction and the intermediate responses from each intermediate tag, wherein at least one of the plurality of intermediate responses from the one or more intermediate tags includes range data associated with a target-hop distance from the intermediate tag to the target tag.