Method and system for synchronizing location finding measurements in a wireless local area network
US6968194B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 2, 2003 |
| Grant date | Nov 22, 2005 |
| Priority date | — |
| Expiry date | May 28, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S5/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and system for synchronizing location finding measurements in a wireless local area network (WLAN) provides a low cost mechanism for correcting location measurements within a WLAN location finding system. Multiple location receivers compute the time-of-arrival (TOA) of a reference transmitter signal, which is generally a beacon signal. The TOAs are collected and reported to a master unit that contains stored predetermined position information for the location receivers. The master unit computes the time-differences-of-arrival (TDOA) between multiple receivers and computes differences between the measured TDOAs and theoretical TDOAs computed in conformity with the predetermined position of each location receiver. The deviations between theoretical and measured TDOAs are collected in a statistical sample set and Kalman filters are used to produce a model of location receiver timebase offset and drift over multiple received beacon signals. The filter outputs are used to then either correct subsequent TDOA measurements for each location receiver, improving the accuracy of subsequent and/or prior TDOA measurements, or commands are sent to the location receivers to calibrate the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.