Performance of an Ultrasonic Ranging Sensor in Apple Tree Canopies

Sensors

Alexandre Escolà³  Santiago Planas³  Joan Ramon Rosell³  Jesús Pomar³  Ferran Camp²  Francesc Solanelles²  Felip Gracia²  Jordi Llorens¹ 

[1] Department of Agro-Food and Biotechnology Engineering, Polithecnical University of Catalonia, Av. Canal olímpic, 15. 08860 Castelldefels, Catalonia, Spain; E-Mails:;Department of Agriculture, Livestock, Fisheries, Food and Environment, Center of Agricultural Mechanization, Generalitat de Catalunya, Av. Rovira Roure, 191. 25198 Lleida, Catalonia, Spain; E-Mails:;Department of Agro-Forestry Engineering, University of Lleida, Av. Rovira Roure, 191. 25198 Lleida, Catalonia, Spain; E-Mails:

关键词: ultrasonic sensor;    distance measurements;    apple tree orchard;    ultrasonic interferences;   

DOI  :  10.3390/s110302459

来源: mdpi

【 摘 要 】

Electronic canopy characterization is an important issue in tree crop management. Ultrasonic and optical sensors are the most used for this purpose. The objective of this work was to assess the performance of an ultrasonic sensor under laboratory and field conditions in order to provide reliable estimations of distance measurements to apple tree canopies. To this purpose, a methodology has been designed to analyze sensor performance in relation to foliage ranging and to interferences with adjacent sensors when working simultaneously. Results show that the average error in distance measurement using the ultrasonic sensor in laboratory conditions is ±0.53 cm. However, the increase of variability in field conditions reduces the accuracy of this kind of sensors when estimating distances to canopies. The average error in such situations is ±5.11 cm. When analyzing interferences of adjacent sensors 30 cm apart, the average error is ±17.46 cm. When sensors are separated 60 cm, the average error is ±9.29 cm. The ultrasonic sensor tested has been proven to be suitable to estimate distances to the canopy in field conditions when sensors are 60 cm apart or more and could, therefore, be used in a system to estimate structural canopy parameters in precision horticulture.

【 授权许可】

CC BY   
© 2011 by the authors; licensee MDPI, Basel, Switzerland.