Multiple Range Estimation Location Using Intermediary Observing Stations
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Solution Overview
Problem
Existing location estimation techniques for mobile devices are hindered by signal multipath and non-line of sight issues, leading to inaccurate location estimates, especially when the time of transmission is unknown or cannot be determined.
Innovation Solution
The method employs Multiple Range Estimation Location (MREL) using Range Rings that account for errors and multipath interference, determining the time of transmission through a functional relationship between the forward and reverse channels, and adjusting for non-line of sight conditions to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Time Difference of Arrival (TDOA) method is used to estimate location when transmission time is unknown, then location estimation can be performed without knowing transmission time, but measurement precision deteriorates due to multipath and non-line of sight errors
Solution Approach 1:
The patent introduces an intermediary system consisting of observing stations and a location server that mediates between the mobile device and the location estimation process. The observing stations capture signals from multiple base stations, and the location server processes these signals to determine both transmission time and location, thereby enabling accurate location estimation without the mobile device needing to know transmission time directly
Solution Approach 2:
The patent replaces the traditional TDOA hyperbolic intersection method with a range ring intersection method. Instead of using time difference measurements that are susceptible to multipath errors, the system uses signal strength-based range estimates to create circular range rings that intersect at the mobile device's location, providing more robust accuracy in non-line-of-sight conditions
2Productivity
If signal arrival time measurements are used for location estimation, then location can be determined using time-based methods, but measurement precision worsens due to signal multipath effects
Solution Approach 1:
The observing stations serve as intermediaries that capture and preserve the original transmission time information from base stations. By having multiple observing stations record the same transmission event, the system can recover accurate transmission time data even when direct mobile-to-base-station timing is unavailable, thereby enabling precise range-based location estimation without multipath degradation
Solution Approach 2:
The patent changes the fundamental parameter from time difference of arrival to range estimation based on signal strength. By transforming the measurement parameter from time-based TDOA to range-based circle intersection, the system achieves location determination that is less sensitive to multipath effects while maintaining productivity
Data Source
AI summary
A system and method of determining the location of a mobile station by determining the time of transmission of a signal by a mobile station and determining range rings at a plurality of reference stations receiving the transmitted signal, where the range rings represent the distance of the mobile station from the plurality of reference stations.