Wireless Device Geo-Location via Summed RTT and AOA Residuals
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Solution Overview
Problem
Existing methods for determining the geo-location of wireless devices using round trip time (RTT) and angle of arrival (AOA) are susceptible to inaccuracies due to noise, multipath propagation, and deviations from IEEE 802.11-2020 standards, leading to inconsistent and inaccurate location estimates.
Innovation Solution
A method that combines RTT and AOA measurements by calculating squared residuals and using a Passfilter technique to minimize the sum of squared residuals (SSR) and fit probability (FP) to improve geo-location accuracy, incorporating a circular error probability (CEP) ellipse for enhanced precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RTT and AOA measurements are used separately for geo-location determination, then the measurement process is simple, but the location accuracy is poor due to noise and multipath propagation
Solution Approach 1:
The patent combines RTT and AOA measurements into a unified geo-location determination process. Multiple measuring stations perform both RTT and AOA measurements, and the results are integrated through a combined cost function that simultaneously optimizes both measurement types, thereby improving location accuracy while managing complexity through systematic integration
Solution Approach 2:
The patent creates a composite measurement approach by integrating multiple measurement types (RTT and AOA) from multiple stations. The combined cost function acts as a composite evaluation mechanism that synthesizes information from different measurement modalities, achieving superior accuracy comparable to using four RTT stations while using only three measuring stations
2Measurement precision
If multiple measuring stations perform RTT measurements, then location accuracy improves, but the time and computational resources required increase
Solution Approach 1:
The patent achieves sufficient measurement accuracy with three measuring stations performing both RTT and AOA measurements, rather than requiring four stations for RTT-only measurements. This partial action approach (using fewer stations) combined with multiple measurement types achieves comparable accuracy while reducing measurement time and computational overhead
Solution Approach 2:
Each measuring station performs dual functions by conducting both RTT and AOA measurements simultaneously. This multi-functionality allows the system to gather diverse measurement data from fewer stations, reducing the overall time and resources required compared to dedicated single-function measurement approaches
Data Source
AI summary
A method for determining a geo-location of a target station. The method includes transmitting a plurality of ranging packets to a target station and receiving a plurality of response packets transmitted by the target station in response. A plurality of round-trip times (RTTs) are determined based on the ranging packets and the response packets. A plurality of angles of arrival (AOAs) are determined based on the response packets. First and second pluralities of squared residuals are calculated for the plurality of RTTs and the plurality of AOAs, respectively. A third plurality of squared residuals is generated by summing the first and second pluralities. A minimum of a sum of the third plurality is calculated to identify best-fit location parameters for the target station. A circular error probability (CEP) ellipse is generated using the best-fit location parameters and a geo-location of the target station is determined based on the CEP ellipse.