Multipath Detection for Indoor Positioning Accuracy
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Solution Overview
Problem
Indoor positioning technologies face challenges in achieving accurate positioning and floor detection due to the limitations of existing systems, which require new infrastructure and are costly and complex to deploy, especially when trying to utilize existing smartphone and building infrastructure effectively.
Innovation Solution
A method that uses signal strength directional derivative fields to mitigate the impact of multipath and reflections in RTT-based positioning methods by determining and storing these fields, allowing for the validation of RTT measurements and improving positioning accuracy by discarding or reducing the weight of invalid measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RTT measurements are used for positioning, then distance information can be obtained, but multipath and reflections cause high-noise measurements or too high distance estimates
Solution Approach 1:
The patent pre-calculates signal strength directional derivative fields based on fingerprint information before actual positioning occurs. These pre-computed fields are stored and later used to quickly validate RTT measurements, allowing the system to identify and discard multipath-affected measurements before they compromise positioning accuracy
Solution Approach 2:
The patent introduces signal strength directional derivative fields as an intermediary validation mechanism between RTT measurements and final positioning results. These derivative fields act as a mediator that helps distinguish valid line-of-sight measurements from invalid multipath measurements by comparing measurement-based derivatives against pre-computed reference derivatives
2Measurement precision
If new infrastructure is deployed for indoor positioning, then positioning accuracy can be improved, but deployment costs and complexity increase
Solution Approach 1:
The patent makes existing WiFi infrastructure serve dual purposes: maintaining wireless communication functionality while simultaneously enabling accurate indoor positioning. By using existing access points for both communication and positioning reference signals, the system eliminates the need for separate positioning infrastructure
Solution Approach 2:
The patent enables the positioning system to self-calibrate and improve accuracy by using fingerprint information collected from normal device movements. The system automatically builds and updates signal strength fields and directional derivative fields without requiring manual site surveys or specialized deployment procedures
3Measurement precision
If manual exhaustive radio surveying is performed, then coverage and accuracy can be achieved, but time and cost increase significantly
Solution Approach 1:
The patent enables automatic fingerprint collection by leveraging background processes in consumer devices that naturally roam through buildings. Devices automatically collect signal strength information during normal operation, and this crowd-sourced data is aggregated to build comprehensive coverage maps without requiring dedicated surveying campaigns
Solution Approach 2:
The patent implements feedback mechanisms where collected fingerprint information is continuously processed to improve the radio map and directional derivative fields. The system learns from accumulated data over time, progressively enhancing positioning accuracy and coverage as more devices contribute measurements
Data Source
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AI summary
Inter-alia, a method is disclosed comprising: determining one or more signal strength directional derivative fields for each respective radio node (140) of one or more radio nodes; and storing the one or more signal strength directional derivative fields; and/or providing the one or more signal strength directional derivative fields. It is further disclosed an according apparatus, computer program and system.