Location measurement process for radio-frequency badges employing path constraints
US7019694B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 5, 2004 |
| Grant date | Mar 28, 2006 |
| Priority date | — |
| Expiry date | Apr 20, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S5/02524
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A process for measuring the location of people and objects carrying radio frequency (RF) transmitters (TXs) that transmit messages to a plurality of RF receivers (RXs) located in a space. Each RX is in communication with a computer of a computer network and forwards data received from the TXs to the network via its associated computer, along with a value indicating the signal strength of the received TX transmission. The signal strengths attributable to the same transmission are used to form a locating signal strength vector which is then compared to exemplary vectors generated from signal strength readings gathered in a calibration procedure from a set of representative locations in the space. In comparing the locating vector to the exemplary vectors, constraints are enforced on movements between locations (e.g., cannot pass through walls) and to probabilistically enforce expectations on transitions between locations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.