Effects of environment on accuracy of ultrasonic sensor operates in millimetre range

Abstract

The growing use of ultrasonic sensor now demands millimetre range of operation with high accuracy. Ultrasonic sensor uses sound waves for its ranging and the speed of sound is influenced by a number of environmental parameters. The objective of this paper is to discuss on the list of environmental parameters which have the major influence on the accuracy of the ultrasonic sensor and also to formulate a simplified mathematical equation to calculate instantaneous speed of sound by taking these influencing parameters into consideration. Comparison result shows the derived simplified equation for calculating instantaneous speed of sound gives maximum percentage error of 0.33 for the temperature range of 0–50 °С. Here we also focus on the steps to calibrate ultrasonic sensor for millimetres range of operation.