05977913 is referenced by 340 patents and cites 4 patents.

To locate a person within a particular room inside a building or, if outside, within a small enough radius that enables a rapid identification of where that person is located, a system of sensors is strategically disposed throughout the building or area. The sensors are calibrated so that upon activation of an alarm the feedback from all of the sensors enables differentiation of the location of the alarm. To locate an object within a defined area, received values output by the sensors are compared to stored reference values received by the sensors when transmitting reference signals. A best fit of the received values against the reference values is performed to determine the location of the person. To create the stored reference values, a calibration of the sensors is performed. This includes transmitting one at a time a plurality of reference signal levels, and measuring an output of each of the sensors after each transmission. One particularly noteworthy aspect of the present invention is that the sensors are coupled to a central computer via AC power lines in the facility in which the person is to be located. In this case, the AC power lines act as the physical interconnection layer of a local area network.

Method and apparatus for tracking and locating personnel
Application Number
Publication Number
Application Date
February 5, 1998
Publication Date
November 2, 1999
Roger Christ
Kenyon & Kenyon
Dominion Wireless
G08B 5/22
G01S 3/02
View Original Source