Method and apparatus for estimating the location of a signal transmitter

Abstract

In accordance with the principles of the present invention, a beaconing device transmits a radio signal that can be detected by a plurality of wireless receivers positioned at various known locations. The receivers form nodes of a wireless network that further includes a control node with which the receivers can communicate. Each receiver that receives the signal from the beaconing device records the signal strength at which it receives the signal from the beaconing device and sends that information to the control node. The control node processes the signal strength information received from all of the receivers and uses it to estimate the location of the beaconing device. Particularly, the controller solves an optimization problem for the coordinates of the beaconing device by determining the set of coordinates for the beaconing device that minimizes the squared error over all of the receivers that receive the signal from the beaconing device between (1) the Euclidian distance between the known coordinates of the receiving device and the estimated coordinates of the beaconing device and (2) the estimated distance between the beaconing device and the particular receiver based on signal strength at that receiver.

Description

FIELD OF THE INVENTION [0001] The invention pertains to a technique for estimating the location of a transmitter based on information from a plurality of receivers. BACKGROUND OF THE INVENTION [0002] There are many situations in which it is desirable to determine the location of a person or object by sensing electromagnetic radiation from the object. Radar would be one such example. With radar, the electromagnetic radiation is not radiation originating from the object or person but is merely reflected off the object or person. In other circumstances, the object or person may be equipped with a positioning device such as a GPS unit that includes a transmitter for transmitting the coordinates of the person or object via radio waves which can be received at a receiver. Such techniques are known in the military for locating lost soldiers. [0003] These techniques, however, require relatively expensive equipment. They are all are circumstances in which it is desirable to track the locatio...

AI Technical Summary

Benefits of technology

[0012] In accordance with the principles of the present invention, a beaconing device transmits a radio signal that can be detected by a plurality of wireless receivers positioned at various known locations. Preferably, the signal transmitted by each wireless beaconing device comprises an ID that uniquely identifies the beaconing device so that the technique c

Problems solved by technology

Such traits might include lack of movement for an extended period of time, failure to go to a particular place in the household, such as the bathroom, on a reasonably regular basis, or too frequent visits to a particular place in the household, such as the bathroom.

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