Error Analysis of Dayu Electronics Ultrasonic Distance Measurement

Whether in liquid or gas, the following factors affect the accuracy of ultrasonic distance measurement.

　　1. Factors affecting ultrasonic distance measurement accuracy in air-coupled conditions:

　　1. Whether the medium is uniform and stable. In a stable propagation medium, the speed of sound is constant. Changes in the gaseous medium or variations in the concentration of the medium will cause changes in the speed of sound propagation. Moreover, such changes are difficult to compensate for. For example, in a sealed tank containing volatile liquids.

　　2. Ambient temperature. When sound waves propagate in a gas, a temperature change of 1 degree causes a change in sound speed of 0.6 m/s, with a rate of change of approximately 0.17%. Therefore, in environments with large temperature measurement errors or temperature gradients, the measurement error will also be relatively large.

　　3. Pressure. Sound speed varies with pressure; generally, higher pressure increases sound speed, while lower pressure decreases it. Changes in pressure can also lead to variations in the intensity of sound radiation and in propagation attenuation. All of these can cause measurement errors.

　　2. Factors affecting ultrasonic distance measurement accuracy in liquid-coupled conditions:

　　1. Medium: Whether the medium is uniform and stable. In a stable propagation medium, the speed of sound is constant. Changes in the gaseous medium or variations in the concentration of the medium will cause changes in the speed of sound propagation. Moreover, such changes are difficult to compensate for. For example, in thick mud, from top to bottom, due to sedimentation, the density of different layers varies significantly, so the sound propagation speed also changes noticeably. At sea, variations in salinity across different sea areas also have a significant impact on sound speed.

　　2. Ambient temperature. When sound waves propagate in a gas, a temperature change of 1 degree causes a change in sound speed of 1 m/s, with a rate of change of approximately 0.06%. Therefore, in environments with large temperature measurement errors or temperature gradients, the measurement error will also be relatively large. In water, due to the effects of sunlight and currents, temperature stratification layers easily form. Consequently, in deeper natural waters, the measurement error of ultrasonic sensors is generally 1% to 2%.

　　3. Pressure. Sound speed varies with pressure; generally, higher pressure increases sound speed, while lower pressure decreases it. Changes in pressure can also lead to variations in the intensity of sound radiation and in propagation attenuation. All of these can cause measurement errors. However, compared to air, the influence of pressure in liquids is smaller than in air.