Vehicle occupant position and velocity sensor for use in occupant restraint system - transmits ultrasonic waves to occupant and back using time period and frequency shift to determine position and velocity of occupant

摘要

The occupant position sensor determines the position of a vehicle occupant relative to a protective device such as an inflatable airbag, when the vehicle is subjected to a crash of sufficient magnitude to require the airbag. An ultrasonic generator transmits a burst of waves which travel to the occupant and back to a receiver. The time period required for the journey determines occupant position and the frequency shift determines the velocity of the occupant relative to the airbag. The airbag is then disabled if the occupant may be injured by its use.