Digital methods for very accurate ultrasonic sensor measurements

Digital signal processing techniques for obtaining high accuracy in ultrasonic distance measurements are presented. The proposed methodologies employ a suitable time frequency representation (Wavelet Transform or Short Time Fourier Transform) to extract the envelope of the reflected pulse echo, together with a suitable pulse detection algorithm (threshold or correlation) for time-of-flight estimation. A complete metrological characterization of the methods, in terms of systematic and random errors, is achieved, demonstrating the high overall performance.