Bandwidth synthesis for wireless location system
US6091362A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 1999 |
| Grant date | Jul 18, 2000 |
| Priority date | — |
| Expiry date | Jan 12, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A wireless location system receives signals transmitted by wireless telephones at a plurality of signal collection sites. To improve the accuracy of the location information, the system synthesizes greater bandwidth, and thus greater time resolution, than would otherwise be available. The location system commands an MTSO to make the wireless transmitter to be located change frequency channels, and a doubly-differenced carrier phase of the transmitted signal, or the time difference of arrival, is observed at each of many frequencies spanning the widest possible bandwidth. The phase-measurement data from these many frequencies are combined to resolve the inherent integer-wavelength ambiguity. To begin the process of ambiguity resolution, single-frequency channel, doubly-differenced, group delay measurements are used to resolve the ambiguity in the doubly-differenced phase difference between the most closely spaced frequency channels. The invention may be utilized to obtain a bandwidth greater than the typical 20 KHz bandwidth of the signals to be cross-correlated (in either the time or frequency domains) in a cellular telephone location application, With such bandwidth synthesis, up …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.