WLAN Position Matching Using Transmitter Identification Segmentation
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Solution Overview
Problem
Current WLAN-based localization methods, such as RSS fingerprinting, face challenges in accurately determining a user's position due to unreliable signal behavior and the risk of false position estimation, especially when the number of matching radio transmitters is small or their signal strengths deviate significantly.
Innovation Solution
A method that filters and weights the measurement values of radio signals by separating transmitters into those with identical and non-identical identifications between the current and reference positions, using a weighting factor to prioritize transmitters with identical identifications and penalize those not received or received in excess, thereby improving the accuracy of position matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RSS fingerprinting is used for localization, then the method can determine position based on signal strength, but the signal behavior is unreliable and false position estimation occurs
Solution Approach 1:
The patent segments the set of radio transmitters into three distinct groups: first group (identical identifications), second group (non-identical identifications), and third group (transmitters not received or received in excess). This segmentation allows the system to treat different transmitter categories differently, applying specific weighting factors to each group to improve overall position determination accuracy while accounting for signal unreliability.
Solution Approach 2:
The patent applies local quality by assigning different weighting factors to different groups of transmitters based on their reliability characteristics. Transmitters with identical identifications receive higher weight (weighting factor > 0.5), while transmitters with non-identical identifications or excess receptions receive lower weight (weighting factor ≤ 0.5). This localized differentiation optimizes the contribution of each transmitter to the position calculation.
2Quantity of substance
If all radio transmitters are used for position matching, then more data is available, but unreliable signal contributions lead to false position estimation
Solution Approach 1:
The patent extracts and separates unreliable signal contributions by identifying transmitters that should be excluded from the matching process. Specifically, transmitters in the second group (non-identical identifications) and third group (not received or excess receptions) are extracted and assigned lower weighting factors, effectively removing their unreliable contributions from the position calculation while retaining useful information from reliable transmitters.
Solution Approach 2:
The patent changes the parameter of weighting factors to control the influence of different transmitter groups. By adjusting weighting factors based on transmitter identification matching and reception reliability, the system optimizes the balance between quantity of measurement values and precision of position matching, preventing unreliable data from compromising accuracy.
3Productivity
If transmitters with non-identical identifications are included in matching, then more transmitters contribute to position determination, but the risk of false coincidence increases
Solution Approach 1:
The patent applies preliminary action by pre-classifying transmitters into groups based on their identification matching before performing position matching. This preliminary classification allows the system to prepare appropriate weighting factors in advance, ensuring that transmitters with non-identical identifications are already marked as less reliable before the actual matching process, thus preventing false coincidences while maintaining efficient processing.
Data Source
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AI summary
An apparatus (30) for determining a coincidence of a position with a reference position, wherein radio signals from fixedly positioned radio transmitters can be received at the position, having means (32) for providing properties (MP(i)) of the radio signals of the fixedly positioned radio transmitters at the position, wherein the provided properties of the radio signals include transmitter identifications identifying the radio transmitters, means (34) for separating the radio transmitters into a first number (Neq) of radio transmitters previously recorded transmitter identifications of which at the reference position are identical with transmitter identifications provided at the position, and into a second number (Nneq) of radio transmitters previously recorded transmitter identifications of which at the reference position and transmitter identifications provided at the position are different, and means (39) for determining a measure of matching for the position on the basis of the provided properties (MP(i)) of the radio signals, wherein both properties (36) of the first number (Neq) of radio transmitters and properties (37; 38) of the second number (Nneq) of radio transmitters are taken into account in the determination of a measure of matching, and wherein the properties of the first number of radio transmitters and the properties of the second number of radio transmitters enter the measure of matching differently.