Sri International

Michael Kirkpatrick

Jeffrey E Casper

Clay Ross

D Scott Seaton

Christian A Gellrich

James Binnion

Michael Cutter

An integrated indoor and outdoor positioning system and method. A first communication unit aperiodically emits an ultrasonic signal. A second communication unit receives the ultrasonic signal and transmits an identification signal in response to receiving the ultrasonic signal. One of the two communication units is placed at a predetermined position and the other of the two communication units is placed with an object. Identification information obtained from the identification signal is used to determine position information indicating that the object is at the predetermined position. The first communication unit is placed at the predetermined position and the second communication unit accompanies the object. Alternatively, the first communication unit accompanies the object and the second communication unit is placed at the predetermined position. One of the two communication units may also include a GPS receiver for receiving GPS signals from a plurality of satellites or pseudolites and computing position information therefrom. The GPS receiver applies differential GPS corrections computed by a GPS reference receiver to improve the accuracy of the position information. Position information is transmitted to a base station over an assigned radio frequency and during a time slot allocated to the communication unit that is transmitting the position information.

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Hayward, CA, United States of America

Michael Kirkpatrick