Low-cost improvement of an ultrasonic sensor and its characterization for map-building

Ultrasonic sensors have often been used as rangefinders in mobile robots. In many cases their use has been reduced to the measurement of distances to the closest object in front of each transducer, in isolation of the rest of the transducers. This paper describes the design, implementation and application of an ultrasonic sensor made up of four transducers suitably set up. Each transducer is equipped with a low cost electronic system, improved as compared with basic versions, so it may be used in conjunction with the rest and provide accurate Time of Flight (TOF) readings. This makes it possible to use triangulation techniques. The new sensor has been characterised for use in map building by means of certainty grids. Copyright (C) 1998 IFAC.