WCDMA Geo-location Accuracy via Time Window Filtering
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Solution Overview
Problem
Conventional methods for determining location estimates in mobile networks face inaccuracies due to clock/time drift, non-deterministic hyperbolas intersection, and Geometric Dilution of Position (GDP) issues, particularly in areas with uneven base station spacing or low cell coverage.
Innovation Solution
The method optimizes location estimates by synchronizing base station timing using measurement data within a specific time window, applying geometric and linear optimizations, and utilizing reference location estimates to address these issues without requiring network hardware or software modifications, leveraging existing data and periodic measurement reports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional mathematical techniques (triangulation, trilateration, multilateration) are used for geo-location, then location estimation can be performed, but accuracy deteriorates due to clock/time drift between base stations and user equipment
Solution Approach 1:
The patent changes the timing parameter by introducing a time window filter that processes only measurements within a specific time range. This filters out measurements affected by clock drift, effectively changing the temporal parameter of the measurements to improve accuracy without requiring hardware synchronization changes.
Solution Approach 2:
The patent performs preliminary filtering of measurements by applying a time window constraint before location estimation. By pre-processing the measurements to exclude out-of-time-window data, the system prepares cleaner input for the location calculation algorithm, improving final accuracy.
2Ease of operation
If hyperbolas intersection solution is used to determine location estimate, then location can be calculated from time difference measurements, but the solution becomes non-deterministic due to inaccuracies in measurement data
Solution Approach 1:
The patent applies geometric optimization that uses feedback from multiple base station measurements to refine the location estimate. The optimization process iteratively adjusts the estimated position to minimize inconsistencies across all hyperbolas, providing a deterministic solution even when individual measurements have errors.
Solution Approach 2:
The patent uses measurements from more base stations than the minimum required for hyperbolas intersection. By incorporating excessive measurements from multiple base stations and applying optimization, the system overdetermines the solution, making it more robust and deterministic despite individual measurement inaccuracies.
3Area of stationary object
If base stations are unevenly spaced or overshoot in coverage, then network coverage can be achieved, but Geometric Dilution of Position (GDP) problem occurs leading to skewed location estimates
Solution Approach 1:
The patent performs preliminary identification and weighting of measurements from base stations with favorable geometric relationships. By pre-assessing the quality of each base station measurement based on geometric considerations, the system prepares optimized input data that compensates for uneven base station spacing before location calculation.
Solution Approach 2:
The patent changes the weighting parameter of different base station measurements based on their geometric relationship to the estimated position and to each other. By dynamically adjusting measurement weights according to geometric quality, the system compensates for GDP effects caused by uneven base station spacing.
4Quantity of substance
If measurement data from all base stations is used for location estimation, then more data is available for calculation, but clock drift and timing errors increase the inaccuracy of the location estimate
Solution Approach 1:
The patent segments the measurement data by applying a time window filter that divides measurements into acceptable and unacceptable groups. Only measurements within the time window are processed, effectively segmenting the data to exclude corrupted measurements while retaining sufficient valid data for accurate location estimation.
Solution Approach 2:
The patent uses a subset of measurement data (only those within the time window) rather than all available measurements. This partial action approach filters out excessive or corrupted data while retaining enough valid measurements to maintain accurate location estimation without the negative effects of including drifted timing data.
Data Source
AI summary
Various methods, systems, and computer program products are disclosed for determining a location estimate of user equipment in a mobile network. For example, a method may include receiving measurement data that includes a time of arrival indication of data communicated between the user equipment and base stations of the mobile network. The method may further include processing only the received measurement data that is within a particular time window and excluding some of the received measurement data outside the particular time window. The method may further include determining a sync value based on the received measurement data within the time window. The sync value may synchronize timing between at least two base stations of the mobile network. The method may include determining a location of the user equipment based on the sync value and the measurement data. The method may include geometric or linear optimization of the determined location estimate.