UWB Pulse Response Matching for NLOS Propagation Detection
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Solution Overview
Problem
UWB location systems face inaccuracies when signal propagation between location base stations and tags is non-line-of-sight due to obstacles, necessitating a method to identify and mitigate this issue.
Innovation Solution
A method and apparatus that calculates similarity values between current and historical pulse responses to determine the type of signal propagation, using metrics like Euclidean distance and cosine similarity, to differentiate between line-of-sight and non-line-of-sight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UWB location system uses pulse response for location determination, then location functionality is achieved, but location accuracy deteriorates under non-line-of-sight propagation conditions
Solution Approach 1:
The system pre-collects reference pulse responses under known line-of-sight conditions and stores them in a database. When a new pulse response is received, the system compares it against these pre-stored references to determine propagation type. This preliminary preparation of reference data enables accurate NLOS detection without requiring real-time environmental knowledge.
Solution Approach 2:
The system transforms the pulse response signal into different parameter representations (time-domain features, frequency-domain features, or trajectory representations) to enhance distinguishability between line-of-sight and non-line-of-sight conditions. By changing the parameter space in which comparison occurs, the system improves detection accuracy.
2Measurement precision
If similarity calculation uses trajectory representation of pulse responses, then detection accuracy is improved, but computational complexity increases
Solution Approach 1:
The pulse response trajectory is divided into key characteristic points or segments for comparison. Instead of comparing entire continuous trajectories point-by-point, the system identifies and compares critical features such as peak positions, arrival times, or significant trajectory points. This segmentation reduces computational burden while preserving detection accuracy.
Solution Approach 2:
The system uses reference pulse responses stored in a database as templates for comparison. These reference copies are pre-processed and stored in various representations (time-domain, frequency-domain, trajectory). When detecting a new pulse response, the system compares it against these pre-existing copies using efficient similarity metrics, avoiding redundant processing.
Data Source
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AI summary
The present invention relates to a method and apparatus for detecting the type of signal propagation, the method comprising: calculating a plurality of similarity values when a location base station in an ultra-wideband location system currently receives a pulse response from a location tag, wherein each of the similarity values represents the degree of similarity between the currently received pulse response and one of a plurality of reference pulse responses, and the plurality of reference pulse responses are pulse responses from at least one location tag that were previously received by the location base station where the type of signal propagation between the location base station and the at least one location tag is a specific type of signal propagation; and determining, based on the plurality of similarity values, a current type of signal propagation between the location base station and the location tag. The method and apparatus can be used to detect the type of signal propagation between the location base station and the location tag in the UWB location system.