Personal location system
US6169484A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 15, 1999 |
| Grant date | Jan 2, 2001 |
| Priority date | — |
| Expiry date | Apr 15, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C9/28
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A monitoring and location system comprising a service center from which movement to and from a prescribed local area and a prescribed wide area is to be monitored. Each member of a class being monitored is provided with a personal RF transponder unit (RFTU). Each RF transponder unit has a digital electronic identification number (DEIN) embedded therein for transmission by RF upon request. RF transceiver interrogation units define specific egress/ingress zones for the prescribed areas. Each interrogation unit being connected to the service center to god signal (1) when an RFTU has egressed or ingressed a prescribed area and (2) the DEIN embedded therein. The RF transceiver interrogation units can determine distance and bearing to a given RFTU and DEIN. When there are a plurality of cell sites encompassing the prescribed areas, an RF transceiver interrogation unit at each of the cell sites, respectively, are connected to the service center. Each RFTU has an emergency signalling component which, when activated, causes a range and bearing measurement to that RFTU to be made and sent to the service center for action.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.