Reverse infrastructure location system and method
US7403120B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 29, 2004 |
| Grant date | Jul 22, 2008 |
| Priority date | — |
| Expiry date | Oct 29, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S2013/466
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and apparatus are provided to locate a terminal within a workspace. Radio frequency identification (RFID) tags are provided in known locations, preferably in, on or adjacent the light fixtures or other workspace infrastructure. The terminal comprises an RFID tag interrogation transceiver, processor and memory. The transceiver interrogates the tags which respond with information correlatable with their unique locations. The terminal determines its locations relative to the known locations of responding tags by, for example, varying its transmit power and/or receiver sensitivity and/or by trilateration using, for example, phase or time difference of arrival measurements on the tag response signals. Once it has determined its own location it may transmit or otherwise announce its location as desired by the user. In a preferred embodiment, the natural electromagnetic radiation and/or RADAR cross section backscatter from fluorescent type fixtures, modulated with their position information, acts as the RFID infrastructure beacon.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.