TIRE-MOUNTED SENSOR AND ROAD SURFACE CONDITION ESTIMATION APPARATUS INCLUDING THE SAME

A tire-mounted sensor includes a vibration detector, an acceleration sensor, a signal processor, and a transmitter. The vibration detector outputs a detection signal according to amplitude of a vibration of the tire. The acceleration outputs a detection signal according to an acceleration of the tire in a radial direction. The signal processor detects a rotational angle of the tire reaching a ground angle during each rotation of the tire, sets a measurement period including a time period during which the rotational angle of the tire is at the ground angle, extracts a ground contact section during which the portion of the tread provided with the vibration sensor is in contact with the ground, in the measurement period, and generates a road surface data based on the detection signal output from the vibration detector during the ground contact section. The transmitter transmits the road surface data.