Positioning system
US7170445B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 13, 2005 |
| Grant date | Jan 30, 2007 |
| Priority date | — |
| Expiry date | May 13, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S19/11
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
For allowing positioning of a GPS receiver within a building, GPS primary positioning signals received by an outdoor receive antenna are up-converted to different carrier frequencies in the 2.4 GHz ISM band and the converted signals are transmitted each by a transmit antenna inside the building, the transmit antennas serving at the same time as access points of a WLAN which is used for transmitting additional positioning data like the positions of the transmit antennas and the signal delay times associated with them. By cycling through the secondary positioning signals received from the transmit antennas, i.e., down-converting each of them during an assigned time slot, and determining clock bias differences in the receiver, the position of the latter is determined using TDOA algorithms.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.