Object detection device and object detection system

An object detection system comprising:

• a transmission/reception unit that has a vibrator capable of transmitting and receiving ultrasound, that causes the vibrator to transmit a plurality of transmission signals at respectively different timings, and that receives each of the plurality of transmission signals returning after being reflected on a circumferentially existing object, as a reception signal;
• an acquisition unit that acquires a first distance serving as a distance up to the object, based on a time difference between a transmission timing of a first transmission signal out of the plurality of transmission signals and a reception timing of a first reception signal which is the first transmission signal returning after being reflected on the object, and that acquires a relative speed of the object, based on a frequency difference between the first transmission signal and the first reception signal;
• an estimation unit that estimates a second distance serving as the distance up to the object at a transmission timing of a second transmission signal to be transmitted subsequently to the first transmission signal, based on the first distance and the relative speed;
• and
• an adjustment unit that adjusts the number of waves or a transmission time of the second transmission signal, based on the second distance.

An object detection system comprising:

• a plurality of object detection devices each including
• a transmission/reception unit that has a vibrator capable of transmitting and receiving ultrasound, that causes the vibrator to transmit a transmission signal which is a chirp signal in which a frequency repeatedly increases or decreases in every predetermined cycle according to a preset pattern, and outputs a detection signal corresponding to circumferentially received ultrasound, and
• an acquisition unit that specifies the transmission signal included in the detection signal and returning after being reflected on a circumferentially existing object, as a reception signal, based on the pattern, and that acquires information relating to the object, based on the transmission signal and the reception signal;
• and
• a setting unit that sets respectively different patterns in the plurality of object detection devices.