DETECTION OF MULTIPATH AND TRANSMIT LEVEL ADAPTATION THERETO FOR ULTRASONIC LOCATIONING

摘要

A system and method for detection of multipath and transmit level adaptation thereto in ultrasonic locationing of a mobile device within an environment includes providing fixed ultrasonic emitters for transmitting ultrasonic bursts at predetermined times. A communication device measuring at least a direct signal of each ultrasonic burst and detecting multipath of each ultrasonic burst by comparing an amplitude of the direct signal with other signals related to the ultrasonic burst. If multipath is detected a controller increasing a transmit power level of the ultrasonic burst to insure the direct signal reliably remains above the detection threshold. If multipath is not detected reduce a transmit power level to the point detection is just possible. Results from non-multipath conditions are more heavily weighted when determining position as they are typically more accurate.