Merging CEP Ellipses for Passive WLAN Geo Location

The patent divides the measurement process into segments by selecting optimal subsets of TOA measurements based on timer drift characteristics. Instead of using all measurements equally, the system segments them into groups with similar drift characteristics, processes each segment separately to generate individual CEP ellipses, and then merges these ellipses to achieve accurate location determination while compensating for drift variations across different time periods.

The patent changes the parameter selection criteria for measurements based on timer drift conditions. By calculating timer drift between different TOA measurements and selecting subsets with minimal drift, the system dynamically adjusts which measurements are used for location calculation. This parameter-based selection allows the system to adapt to changing drift conditions and maintain accuracy over time.

The patent extracts only the most relevant measurements for location calculation by selecting optimal subsets based on timer drift criteria. Instead of processing all available TOA measurements, the system identifies and extracts subsets with minimal drift characteristics, generating CEP ellipses from these selected measurements. This extraction approach reduces processing complexity while maintaining the benefits of using multiple measurements.

The patent applies partial action by using only the necessary subset of measurements required for accurate location determination rather than all available measurements. By selecting optimal subsets based on drift characteristics and merging the resulting CEP ellipses, the system achieves accurate location with fewer processed measurements, reducing computational complexity while maintaining or improving accuracy compared to using all measurements.