Occupant position system and method using ultrasonic technology

A method of detecting the position of a main body part of an occupant as being a main target and tracking this main target while other secondary objects are placed partially in front of it, the method comprising the steps of:

• A) transmitting an ultrasound pulse of a determinable period toward the occupant, and starting a time counter;
• B) capturing the time count generated by the time counter whenever any received signal exceeds a determinable threshold;
• C) separating and analyzing the previously captured time counts to determine how many objects are located at different distances and then calculating these different distances;
• D) depending upon how many objects were detected, moving a sensing threshold level up or down, to compensate for different reflection factors resulting from different reflection materials, until a reasonable number of objects has been detected;
• E) building a history of objects detected at different distances for several transmission periods;
• F) analyzing this history to determine the position of the main body as being the most furthest object seen as a result of the history;
• G) updating this history after every transmit period and continuing to analyze it to lock onto the position of the main body while ignoring other secondary objects placed in front of it;
• H) flagging the system whenever a secondary object is being seen repeatedly within an Automatic Suppression Zone;
• I) repeating the process of building and analyzing a history of objects detected any time the system determines that it has lost its main target.