Resolving Crosstalk of Sonar by Applying Nonlinear Filter Based on the Sliding Mode

Ultrasonic wave sensors are widely used in mobile robots to measure distance. Time-of-flight (TOF) ranging generally used to measure distance measures the round-trip time required for a pulse of emitted energy to travel to a reflecting object and echo back to a receiver. In actual ultrasonic wave sensor (sonar) use, we must consider the existence of multiple sonars in an environment in which one may receive the echo of a signal emitted by other sonars. The receiving sonar cannot determine whether the echo was triggered by its own signal so erroneous distance shorter than actual distance is observed. This problem is generally known as crosstalk. We present a novel way to filter data generated by crosstalk using a nonlinear digital filter based on the sliding mode. Experimental verified show the validity of our proposed method.