Wi-Fi Location Determination Using Signal Profile Matching
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Solution Overview
Problem
Current location determination methods based on Wi-Fi signal strength are prone to inaccuracies due to variations in signal strength over time and interference from new or removed access points, requiring precise matching that wastes processing power and is unnecessary for coarse location indications, which are often sufficient for user contexts like being at home or office.
Innovation Solution
A method for determining a user's location by comparing the signal strengths of surrounding Wi-Fi access points to a stored profile, ignoring non-observed access points and using a scoring system to tolerate changes in the access point landscape, allowing for coarse location determination without excessive processing and enabling the merging of profiles for multiple contexts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precise location determination is performed using Wi-Fi signal strength matching, then location accuracy is improved, but processing power consumption increases and system complexity increases
Solution Approach 1:
The patent segments the location determination process into two distinct stages: (1) a rough location determination phase that uses simplified matching criteria to identify potential candidate locations, and (2) a precise verification phase that is only executed for candidates passing the initial filter. This segmentation reduces overall processing power consumption while maintaining location accuracy for final results.
Solution Approach 2:
The patent applies partial action by performing complete precise matching only for a subset of candidate locations that pass the initial rough screening. Instead of executing full precise matching for all possible locations, the system performs partial verification on selected candidates, reducing processing energy while preserving measurement precision for the final location determination.
2Measurement precision
If precise location determination is performed using Wi-Fi signal strength matching, then location accuracy is improved, but device complexity increases
Solution Approach 1:
The patent divides the location determination system into two functional modules: a rough matching module that implements simple filtering criteria, and a precise matching module that performs detailed verification. This segmentation reduces device complexity by organizing the system into manageable stages with clearly defined responsibilities, while still achieving high location accuracy through the combination of both modules.
Solution Approach 2:
The patent implements a two-stage verification process where only partial precise matching is performed on selected candidate locations rather than conducting full precise matching on all possibilities. This approach reduces system complexity by limiting the scope of complex operations to necessary cases only, while maintaining measurement precision for final location determination.
3Measurement precision
If signal strength matching is performed against all stored access points, then measurement precision is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary rough matching before precise location determination to pre-filter and identify candidate locations that are likely to be correct. This preliminary action eliminates obviously incorrect candidates in advance, reducing the number of access points that need to be compared during the subsequent precise matching phase, thereby decreasing processing time while maintaining measurement precision.
Solution Approach 2:
The patent segments the access point comparison process into two phases: (1) rough comparison phase that quickly evaluates basic criteria to identify candidate locations, and (2) precise comparison phase that performs detailed signal strength matching only on identified candidates. This segmentation significantly reduces processing time by avoiding exhaustive comparison with all stored access points, while preserving location detection accuracy through the subsequent verification phase.
4Use of energy by moving object
If coarse location indication is used instead of precise location determination, then processing power consumption is reduced, but location accuracy deteriorates
Solution Approach 1:
The patent implements a segmented approach where coarse location indication serves as the first stage for reducing processing power consumption, followed by a second stage that provides precise location determination when needed. This segmentation allows the system to operate in low-power mode for general location awareness while maintaining the capability for high-accuracy location determination, thus resolving the contradiction between energy consumption and location accuracy.
Solution Approach 2:
The patent applies partial precise matching only when necessary rather than continuously performing full precise location determination. The system uses coarse location indication as the default (partial action) to conserve processing power, and selectively activates precise matching only when higher accuracy is required, thus balancing energy consumption with location accuracy based on actual needs.
Data Source
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AI summary
A method for determining a location of a mobile apparatus based on the presence of wireless access point signals. The received wireless signal strength from a plurality of observed wireless access points is compared with profiles each relevant to a different user context and containing a plurality of previously registered wireless access point signal strengths around a previously registered location. The location of the mobile apparatus is determined based on the profile most closely matching the collection of observed wireless access points. Wireless access points present in the profile but not observed are ignoring during the matching process.