Method and apparatus for tracking mobile devices using tags
US6720888B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 2001 |
| Grant date | Apr 13, 2004 |
| Priority date | — |
| Expiry date | Nov 19, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K17/0022
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A signpost (11, 241-256, 322, 612, 623, 626-628, 652, 661, 682, 686, 703) transmits low frequency signals to a beacon tag (12, 271-275, 301-316, 395-397, 616-618, 641-643, 653, 656-657, 662-664, 679, 708, 711), which in turns transmits high frequency signals containing a signpost code from a received signpost signal to a reader (13, 261, 319, 521-530). The signpost can be mounted on one mobile device and the beacon tag on another mobile device, in order to determine when those mobile devices are in close proximity. Further, a sensor (32) can be provided to detect the presence of a mobile device, and to cause the signpost to change the signpost code in its transmitted signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.