Ultrasonic positioning and tracking system

摘要

A method of tracking an object within a surveillance area having a predetermined linear extent. One or more ultrasound transducers are fixed to the object. A plurality of background units are placed at known positions in the area, each unit including an ultrasound transducer. One or more ultrasound waves are transmitted between the object and the plurality of background units. The ultrasound waves are received if they have propagated between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area. A characteristic of the received ultrasound waves is determined, and coordinates of the object are determined responsive to the characteristic.