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

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 s...

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Detalles Bibliográficos
Autores: Gamarra Diezma, Juan Luis, Miranda Fuentes, Antonio, Llorens, Jordi, Cuenca, Andrés, Blanco Roldán, Gregorio L., Rodríguez Lizana, Antonio
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2015
País:España
Institución:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/46281
Acceso en línea:http://hdl.handle.net/11441/46281
https://doi.org/10.3390/s150202902
Access Level:acceso abierto
Palabra clave:ultrasonic sensor
canopy characterization
olive tree
sensor accuracy
sensor interference
Descripción
Sumario: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.