摘要 |
The presence/absence of an object, movement of the object, the direction of movement, the speed of movement, the shape of the object, the quantity of objects and time information related to these factors are detected without installing a means for transmission. An antenna device (1) has a function of receiving radio waves (EW1 to EW24) transmitted by GPS satellites and outputs a detection signal when the reception of the radio waves (EW1 to EW24) transmitted by the GPS satellites is blocked by an object (A). A signal processing device (2) detects the object (A) based upon the detection signal provided by the antenna device (1). <IMAGE> |