Trilateration Peer Device Selection Using RSSI Weighting
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Solution Overview
Problem
Trilateration processes for mobile computing device location identification in indoor environments face inaccuracies due to variations in signal strengths and sub-optimal selection of peer devices, leading to errors in determining the precise location of a mobile computing device.
Innovation Solution
The method involves selecting nearest peer devices based on received signal strength indicator (RSSI) measurements and assigning them to weighted buckets to improve the accuracy of distance measurements, ensuring a physical spread that increases the number of intersection points for location determination, while also considering the movement of the device to refine the calculated position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If trilateration is performed using all received peer devices, then more intersection points are obtained, but measurement precision deteriorates due to sub-optimal peer device selection and signal strength variations
Solution Approach 1:
The patent segments the set of all peer devices into multiple groups or buckets based on distance ranges. Instead of using all peer devices uniformly, the system divides them into categories (e.g., near, medium, far) and selectively uses devices from specific segments, thereby improving measurement precision by excluding sub-optimal distant devices while still obtaining sufficient intersection points from the segmented groups.
Solution Approach 2:
The patent applies local quality by assigning different weights to peer devices based on their distance from the mobile device. Nearby peer devices are assigned higher weights due to their more reliable signal strength measurements, while distant devices receive lower weights. This differential weighting approach improves location determination accuracy by emphasizing high-quality local measurements over lower-quality distant ones.
2Measurement precision
If nearest peer devices are selected based on RSSI measurements, then measurement precision improves, but device complexity increases due to sorting and bucket assignment processes
Solution Approach 1:
The patent applies preliminary action by pre-sorting peer devices into distance-based buckets before performing trilateration calculations. The system预先 categorizes peer devices into near, medium, and far groups based on their distance from the mobile device, so that when location determination is needed, the sorting and selection process has already been completed, reducing real-time processing complexity while maintaining high measurement precision.
3Measurement precision
If peer devices are assigned to weighted buckets based on distance, then location determination accuracy improves, but loss of time increases due to additional sorting and classification operations
Solution Approach 1:
The patent performs the sorting and bucket assignment operations in advance, before the actual location determination is required. By pre-organizing peer devices into distance-based weighted buckets, the system eliminates the need to perform these computationally intensive operations in real-time when a location fix is needed, thereby reducing processing time while maintaining improved location accuracy through the use of distance-weighted peer device selection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy and performance of trilateration by reducing errors associated with wireless signal propagation and user movement, providing a more reliable and stable location determination, thus improving the user experience.
Implementation Method 1
the distance between the STA and PD being calculated using wireless signal strength measurements and a wireless propagation model (e.g., Freespace Path Loss Model or Two Ray Model)
Data Source
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AI summary
Embodiments of the invention address how trilateration processes are affected by physical placement and sub-optimal selection of peer devices (PDs) used to obtain a location of a mobile computing device. Embodiments of the invention describe processes for selecting nearest PDs over further PDs, as received signal strength indicator (RSSI) measurements are more reliable? i.e., said "nearest PDs" provide more accurate distance measurements while improving the probability of finding more intersection points. Embodiments of the invention further describe selecting a physical spread of PDs to help increase the number of intersection points while helping distinction/resolution of the location of the mobile device in both the 'x' (longitude) and the 'y' (latitude) directions. Embodiments of the invention further enhance trilateration processes by utilizing dampening values for calculated location poll data.