A Large-Range Ultrasonic Distance Measuring Device Based on Improved Time Difference Method

Ultrasonic ranging by using the time difference method generally has the problems of inaccurate measurement of echo arrival time and small range. To solve the above problems, firstly, this paper proposes a method to detect the arrival time of the echo by using the inflection point of the echo envelope with the combination of logarithmic characteristics of the logarithmic amplifier and improves the peak detection of the traditional TDOA by changing the characteristic point of the arrival time of the echo. Secondly, an ultrasonic distance measuring device is designed, in which the transmitting power and the sensitivity of the receiving end can be adjusted automatically with the echo signal strength to improve the measurement accuracy and broaden the measuring range. The experimental results show that the range of the device is expanded from 0.5-12 m to 0.3-20 m, and the distance measurement error is reduced from 1% to 0.5% when the improved time difference method is adopted and the self-tuning of the transmitting and receiving parameters is enabled. It shows that the improved time difference method can improve the measurement accuracy and can effectively expand the ultrasonic ranging range by using the self-tuning of the transmitting and receiving parameters.