A method comprising: providing an autonomous vehicle (AV) with a first estimated position of a target; directing the AV to travel toward the first estimated position at a constant velocity; receiving echo signals of transmitted sonar signals, the echo signals indicating a range and an azimuth of the target; determining a depth difference of the AV and the target based on the received echo signals, the depth difference being determined based on changes to the range and azimuth of the target over time; and in response to a depth difference existing, re-directing the AV toward a second estimated position of the target generated from the depth difference.

A method comprising: providing an autonomous vehicle (AV) with a first estimated position of a target; directing the AV to travel toward the first estimated position at a constant velocity; receiving echo signals of transmitted sonar signals, the echo signals indicating a range and an azimuth of the target; determining a depth difference of the AV and the target based on the received echo signals, the depth difference being determined based on changes to the range and azimuth of the target over time; and in response to a depth difference existing, re-directing the AV toward a second estimated position of the target generated from the depth difference.

A collision prevention device is mounted on a vehicle and prevents collision against an obstacle by controlling a driving system of the vehicle. This collision prevention device includes an obstacle sensor, an obstacle detection area setting unit, a detector and a vehicle controller. The obstacle sensor transmits one of a light wave, a radio wave and an ultrasonic wave to a predetermined obstacle detection area, and receives a reflected wave of one of the light wave, the radio wave and the ultrasonic wave. The obstacle detection area setting unit sets the obstacle detection area of the obstacle sensor. The detector detects the obstacle in the obstacle detection area based on a detection result of the obstacle sensor. The vehicle controller controls the driving system of the vehicle based on a result of the detection of the detector, and according to the obstacle detection area set by the obstacle detection area setting unit.

A collision prevention device is mounted on a vehicle and prevents collision against an obstacle by controlling a driving system of the vehicle. This collision prevention device includes an obstacle sensor, an obstacle detection area setting unit, a detector and a vehicle controller. The obstacle sensor transmits one of a light wave, a radio wave and an ultrasonic wave to a predetermined obstacle detection area, and receives a reflected wave of one of the light wave, the radio wave and the ultrasonic wave. The obstacle detection area setting unit sets the obstacle detection area of the obstacle sensor. The detector detects the obstacle in the obstacle detection area based on a detection result of the obstacle sensor. The vehicle controller controls the driving system of the vehicle based on a result of the detection of the detector, and according to the obstacle detection area set by the obstacle detection area setting unit.

An ultrasonic measuring system is described for detecting an obstacle using a resonant transducer element for transmitting an ultrasonic pulse and for generating a received signal which includes the ultrasonic echo pulse reflected from the obstacle, the transducer element generating a decay signal having its resonance frequency after transmitting an ultrasonic pulse. The ultrasonic measuring system includes an evaluation unit having a control unit which is designed to activate the transducer element for transmitting the ultrasonic pulse with the aid of a frequency-modulated transmitted signal generated by the control unit, the frequency modulation taking place with the aid of a modulation signal in such a way that the signature of the ultrasonic pulse differs from that of the decay signal. The evaluation unit is designed to recognize the echo pulse based on an evaluation of a correlation signal which is generated with the aid of at least one correlation filter and which originates from the correlation of the signal generated by the resonant transducer element with the transmitted signal. Furthermore, a corresponding method is provided for detecting an obstacle with the aid of ultrasound, as well as a vehicle assistance system having the ultrasonic measuring system.