Testing Accuracy of Long-Range Ultrasonic Sensors for Olive Tree Canopy Measurements

Sensors

Juan Luis Gamarra-Diezma¹  Antonio Miranda-Fuentes¹  Jordi Llorens¹  Andrés Cuenca¹  Gregorio L. Blanco-Roldán¹ 

[1] Dpto. de Ingeniería Rural, Área de Mecanización y Tecnología Rural, Universidad de Córdoba, Córdoba 14005, Spain; E-Mails:

关键词: ultrasonic sensor;    canopy characterization;    olive tree;    sensor accuracy;    sensor interference;   

DOI  :  10.3390/s150202902

来源: mdpi

【 摘 要 】

Ultrasonic sensors are often used to adjust spray volume by allowing the calculation of the crown volume of tree crops. The special conditions of the olive tree require the use of long-range sensors, which are less accurate and faster than the most commonly used sensors. The main objectives of the study were to determine the suitability of the sensor in terms of sound cone determination, angle errors, crosstalk errors and field measurements. Different laboratory tests were performed to check the suitability of a commercial long-range ultrasonic sensor, as were the experimental determination of the sound cone diameter at several distances for several target materials, the determination of the influence of the angle of incidence of the sound wave on the target and distance on the accuracy of measurements for several materials and the determination of the importance of the errors due to interference between sensors for different sensor spacings and distances for two different materials. Furthermore, sensor accuracy was tested under real field conditions. The results show that the studied sensor is appropriate for olive trees because the sound cone is narrower for an olive tree than for the other studied materials, the olive tree canopy does not have a large influence on the sensor accuracy with respect to distance and angle, the interference errors are insignificant for high sensor spacings and the sensor's field distance measurements were deemed sufficiently accurate.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.