US Patent 11378671 Coarse to fine movement detection in vehicles

A system and method for identifying the presence of an occupant in a vehicle. The system includes a first sensor positioned within a seating area of a seat and having a corresponding sensitive zone passing through the seating area vertically, and a second sensor positioned within a back rest area of the seat and having a corresponding sensitive zone passing through a chest area of an occupant horizontally. The first sensor is adapted to sense coarse movements adjacent to and farther from the sensor while the second sensor is adapted to capture both coarse and finer movements, such as breathing and heartbeats.