Indoor Positioning Validation via WLAN Signal Distribution Matching
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Solution Overview
Problem
Current satellite-based positioning technologies are ineffective indoors due to signal penetration issues, leading to inaccurate navigation and positioning challenges in indoor environments.
Innovation Solution
A method that involves a mobile device obtaining radio signal measurements and matching them with assistance data to estimate and validate its position, using a distribution of signal characteristics to determine the validity of the estimated position, thereby improving indoor positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If satellite signal based positioning technologies are used outdoors, then positioning performance is satisfactory, but the technology cannot penetrate through walls and roofs for indoor positioning
Solution Approach 1:
The patent introduces WLAN access points as intermediary transmitters to establish indirect positioning paths through building structures. Instead of relying on satellite signals that cannot penetrate walls, the system uses locally deployed WLAN transmitters that can be received indoors, serving as mediators between the positioning system and indoor locations.
Solution Approach 2:
The patent replaces the satellite-based electromagnetic positioning system with a terrestrial WLAN-based radio signal positioning system for indoor environments. This substitution involves using mobile device measurements of WLAN signal characteristics (RSSI, TOA, TDOA) instead of satellite signal measurements to determine position.
2Reliability
If dedicated indoor positioning solutions based on pseudolites or Bluetooth are deployed, then indoor positioning capability is achieved, but device complexity and infrastructure requirements increase
Solution Approach 1:
The patent repurposes existing WLAN access points, which are already deployed for networking purposes, to also serve as positioning transmitters. This multi-functional use of infrastructure eliminates the need for separate dedicated positioning hardware like pseudolites or Bluetooth beacons, reducing overall system complexity.
Solution Approach 2:
The system leverages the existing WLAN infrastructure that already serves communication purposes to simultaneously provide positioning services. The WLAN access points self-serve dual functions without requiring additional dedicated positioning infrastructure, reducing deployment complexity.
3Measurement precision
If WLAN based positioning solutions collect fingerprints from mobile devices, then positioning accuracy improves, but data collection requires user consent and participation
Solution Approach 1:
The patent implements a feedback mechanism where mobile devices continuously report measured WLAN signal characteristics to a server, which updates the fingerprint database. This ongoing feedback loop allows the system to improve positioning accuracy over time using data from multiple users while maintaining a distributed data collection approach.
4Productivity
If a position estimate is calculated using WLAN signal measurements, then positioning functionality is provided, but the validity of the position estimate cannot be verified
Solution Approach 1:
The patent employs feedback through distribution matching validation, where the measured signal characteristics are compared against expected distributions from the fingerprint database. This feedback mechanism provides validity verification by assessing whether the measured characteristics conform to known patterns at the estimated position.
Solution Approach 2:
The patent replaces traditional distance-based validation methods with a distribution-based validation approach. Instead of relying solely on geometric constraints, the system substitutes statistical comparison of signal characteristic distributions to verify position validity, providing a more robust validation mechanism for WLAN positioning.
Data Source
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AI summary
An apparatus obtains results of measurements by a mobile device on radio signals transmitted by a plurality of transmitters, the results of measurements comprising characteristics of the radio signals at the location of measurement. The apparatus estimates a position of the mobile device based on the obtained results of measurements and based on assistance data including information on expected characteristics of radio signals of various transmitters at various locations. The apparatus matches a distribution of characteristics of radio signals in the obtained results of measurements with a reference distribution of characteristics of radio signals. Alternatively or in addition, the apparatus determines matching transmitters for which characteristics are available in the results of measurements and in the assistance data, and matches a determined expected distribution for the matching transmitters with a predetermined reference distribution. A result of any matching is provided as an indication of the validity of the estimated position.