Proximity-based magnetic field generator for controlling operation of RF burst-transmitting tags of geolocation system
US6853687B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 2001 |
| Grant date | Feb 8, 2005 |
| Priority date | — |
| Expiry date | Mar 8, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V15/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An object tracking system for locating radio-tagged objects within a monitored environment has a plurality tag transmission readers that detect RF transmissions from the tags, and generate output signals representative of the time-of-arrival of first-to-arrive tag transmissions. An object location processor processes the first to arrive signals in accordance with a multilateration algorithm to geolocate a tag. In order to modify the operation of a tag that comes within a prescribed region of the monitored environment (such as passing through a doorway), one or more relatively short range, magnetic field proximity-based, tag-programming ‘pingers’, are placed proximate to the region. A magnetic field receiver on the tag detects the field generated by the pinger and causes the tag to change operation such as increase its RF transmission rate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.