Sensing the position of a mobile object relative to a fixed object via ultrasound and infrared

摘要

A position sensing apparatus is disclosed comprising an ultrasonic transmitter 12, an ultrasonic receiver 10, an infrared transmitter 202, a 2-dimensional infrared receiver 200 such as a camera, and a timer. The apparatus is divided into a mobile 2 and a fixed component 11 separate from one-another. The ultrasonic and infrared components are located adjacent one another in heterogeneous pairs on each respective component. The apparatus further includes an image processing means and a control means for coordinating the functions of said receivers, transmitters and timer. The apparatus transmits an ultrasonic pulse between the ultrasonic transmitter 12 and receiver 10 and simultaneously starts the timer. The timer is stopped when the ultrasonic pulse has been received thus measuring its time of flight. The apparatus further determines a 2-dimensional relative angular position of the infrared transmitter 202 and receiver 200 by processing the image received by the receiver 200. The ultrasonic distance measurement and infra-red angular measurement together provide a 3-dimensional position fix. The fixed component 11 may be coupled to a PC or games console.