Ultrasonic Distance Measurement Method With Crosstalk Rejection at High Measurement Rate

Abstract

This paper introduces a computationally intensive method for measuring distance at high measurement rates using chaotic pulse-position (CPPM) signals and single-bit signal processing in a single ultrasound sensor system. To prevent crosstalk from other ultrasonic sensor systems, a chaotic system is used, and the ultrasonic pulses are transmitted as a pulse sequence generated by CPPM. After receiving the ultrasound signal, the single-bit signal was generated by a fast Fourier transform threshold, which also functions as an environmental noise filter. Single-bit signal processing has been adopted to reduce the computational load when cross correlating the transmitted and received signals for time-of-flight calculations. Single-bit signal processing has more than 100 times memory saving effect in this paper. Additionally, as the signal-to-noise ratio increases, extension of the maximum measurable distance in the ultrasonic distance sensor system is expected. The simulation shows the crosstalk rejection performance of the proposed method, and the experimental results confirm the improvement of the measurement speed by the proposed method.