Using coded signals to benefit from ultrasonic sensor crosstalk in mobile robot obstacle avoidance

One problem oftentimes observed with arrays of multiple ultrasonic sensors (sonars) in obstacle detection and avoidance systems is crosstalk. The paper presents a method in which data generated by crosstalk is actually used to generate more reliable and accurate object detection. This is accomplished by assigning a unique code to the signals emitted by each sonar, so that the source sonar can be identified even if its signal's echo is received by another sonar. Using geometric interpolation between the various sonars increases the accuracy of the measurements, overcoming their limited resolution. Experimental results show the potential of our system for mobile robotics obstacle detection and avoidance, as well as for localization using map-matching techniques.