Geo-locating Wireless Devices Using Dynamic RTT Binning
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Solution Overview
Problem
Existing geo-location methods for wireless devices using round-trip times (RTTs) face challenges in distinguishing true RTT measurements from false ones, especially in noisy environments, requiring calibration of correlation thresholds that vary with background noise levels, leading to reduced sensitivity.
Innovation Solution
A dynamic binning method that places RTT measurements into bins based on their counts and averages, selecting bins with the highest and next highest counts to determine the geo-location of a target station, independent of background noise levels, thereby rejecting noise-induced false RTTs and enhancing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correlation threshold calibration is performed to distinguish true RTT measurements from false ones in noisy environments, then measurement precision is improved, but device complexity increases due to the need for calibration procedures
Solution Approach 1:
The system automatically determines correlation thresholds through self-calibration using historical RTT data and environmental noise characteristics, eliminating the need for manual calibration procedures. The measuring station autonomously adjusts thresholds based on observed noise patterns and true RTT measurements, making the system self-adapting to changing environmental conditions.
Solution Approach 2:
The system performs preliminary calibration by collecting and analyzing RTT measurements during an initial period to establish baseline correlation thresholds before actual geo-location measurements begin. This preliminary action prepares the system in advance, so that when measurements are taken, the calibration is already complete and no additional complexity is required during operation.
2Reliability
If correlation threshold calibration is performed to reject noise-induced false RTTs, then reliability is improved, but loss of time occurs due to calibration requirements
Solution Approach 1:
The system continuously updates correlation thresholds in the background using ongoing RTT measurements and noise observations, rather than performing discrete calibration steps. This continuous operation ensures that the system maintains high reliability without interrupting the geo-location measurement process, eliminating time loss associated with periodic recalibration.
Solution Approach 2:
The system performs preliminary calibration during system initialization or during periods when measurements are not critical, so that when actual geo-location measurements are needed, the calibration is already complete. This preliminary preparation eliminates the need for time-consuming calibration during critical measurement phases.
3Measurement precision
If correlation threshold calibration is performed to enhance sensitivity, then measurement precision is improved, but ease of operation deteriorates due to calibration requirements
Solution Approach 1:
The measuring station automatically determines and adjusts correlation thresholds based on environmental conditions and measurement quality, eliminating the need for operators to manually calibrate the system. The self-service mechanism maintains high sensitivity and precision while keeping the system easy to operate, as no specialized calibration knowledge or manual intervention is required.
Solution Approach 2:
The system dynamically adjusts correlation thresholds in response to changing environmental conditions and noise levels, rather than using fixed thresholds. This dynamic adaptation maintains optimal sensitivity and measurement precision across varying conditions without requiring operators to manually adjust parameters, thus preserving ease of operation while enhancing measurement quality.
Data Source
AI summary
A method for determining a geo-location of a target station is provided. The method includes receiving a plurality of RTTs over a plurality of successive time intervals. Each successive time interval is equal to a predetermined amount of time. The plurality of RTTs is placed into a plurality of bins. Each bin has a predetermined time width and a count of RTTs placed in the bin. A bin with a highest count of RTTs (maxCb) and another bin with a next highest count of RTTs are selected and a maximum count ratio determined. The bin with maxCb to a maximum bin value is set based at least on a predetermined threshold of the maximum count ratio. During a next successive time interval, the RTTs that are placed in the bin that is set to the maximum bin value are selected to determine the geo-location of the target station.