A high-resolution sensor based on tri-aural perception

The authors present a high-resolution sensor composed of three ultrasonic sensors, one transmitter/receiver and two extra receivers, which allows a significant improvement in the information-extraction process. With this sensor the position (distance and bearing) of all isolated objects in an approximately 25° field of view can be determined using information contained in one single snapshot of a moderately complex scene. Within limits, the sensor system can also discriminate between different types of reflectors, in particular, walls and edges, based on their radius of curvature. These results are all based on the determination of the arrival times of the echoes present at the three receivers. A noise model that accounts for the measured variations of the arrival times is used to derive limits on the resolution of the results provided by the sensor. Based on this model it is shown that, to a large extent, the sensor results are impervious to measurement variations common to all three receivers. Results obtained in a realistic environment are compared with those obtained from a conventional time-of-flight sensor