Positional uncertainty assessment and complex obstacle detection of an ultrasonic sensor ring with overlapped beam pattern

This paper presents the positional uncertainty assessment and the complex obstacle detection of an ultrasonic sensor ring with overlapped beam pattern. Due to beam overlap between adjacent ultrasonic sensors, the entire sensing range of an individual ultrasonic senor can be divided into three smaller sensing subzones. First, the concept of collision free region of each ultrasonic sensor with reference to the center of an ultrasonic sensor ring is introduced. Second, the effective beam width of an overlapped ultrasonic sensor ring is defined to assess the positional uncertainty in obstacle detection. Third, high resolution single obstacle detection can be made based on the combination of two adjacent ultrasonic sensors detecting a given obstacle. Fourth, high resolution multiple obstacle detection can be made based on the inequality relationships among the obstacle distances by three consecutive ultrasonic sensors.