Thickness measurement system and method for vehicle occupant detection

摘要

A passenger detection system is provided. The passenger detection system utilizes an oscillation circuit that causes an antenna electrode to emit an electric field that is disrupted by the electrical characteristics of an object placed on the seat. This disruption alters the current and phase of the signal in the antenna electrode. By comparing the current flowing in the antenna electrode and/or the difference between the phase of the signal in the antenna electrode and the oscillation circuit output signal with predetermined threshold values, it is possible to detect the presence of a passenger in a reliable and inexpensive manner. The determination is made with a two layer electrode arrangement, including smaller and larger electrodes. The two layers allow calculation of an amount of compression on the seat. The amount of compression is used to characterize the passenger.