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.

主权项

1. A system for detection of multipath and transmit level adaptation thereto in ultrasonic locationing of a mobile device within an environment, the system comprising:
a plurality of fixed ultrasonic emitters within the environment, the emitters operable to transmit ultrasonic bursts at predetermined times to a communication device located within the environment; a communication device operable to measure at least a direct signal of each ultrasonic burst and detect multipath of each ultrasonic burst by comparing an amplitude of the direct signal with other signals related to the ultrasonic burst; and a controller coupled to the emitters, wherein if multipath is detected the controller is operable to adapt a transmit power level of the ultrasonic burst until an amplitude of the direct signal is above a threshold in detecting whereby multipath is no longer detected, and wherein if multipath is not detected the controller is operable to locate the communication device using the direct signal of each of a plurality of ultrasonic bursts.