Ultrasonic Sensor for Mobile Mini-Robots Using Pseudo-Random Codes

Ultrasonic sensors enable mobile autonomous systems to obtain information about obstacles in large environments. In the presented work, taking the limited energy resources of a mobile robot into account, only one transmitter is used. The employment of two receivers permits the calculation of the distance and direction of objects. Using pseudo-random sequences, simultaneously transmitting and receiving with the continuous perception of the environment is possible. The sequences are modulated in order to optimise the signal-to-noise ratio and energy consumption with respect to the transducers’ bandwidth. With the gained signals the echo-intensity £eld is calculated for object detection. Furthermore, several robots could operate in the same region applying orthogonal sequences.