Pseudolite-augmented GPS for locating wireless telephones
US6771625B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 10, 2000 |
| Grant date | Aug 3, 2004 |
| Priority date | — |
| Expiry date | Oct 30, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/46
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Ground-based pseudolites support accurate determination of mobile receiver locations by broadcasting CDMA signals interleaved by a TDMA system. Pseudolites synchronize signal transmissions with an accurate timing reference, such as can be derived from GPS satellites. Adjacent pseudolites broadcast CDMA signals at different times, eliminating near-far signal interference between pseudolites. A mobile receiver, typically a cellular telephone, receives and enables determination of times of arrival (TOA) of the pseudolite signals. A location processor associated with the mobile receiver may access an internal database of pseudolite locations, or pseudolite location information may be encoded in pseudolite transmissions. The location processor uses pseudolite location information and TOA to determine mobile receiver location. The TDMA pseudolite-based system may augment the GPS to provide more accurate location information than is available from the GPS alone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.