2022 Volume 84 Issue 5 Pages 332-338
A boom height measurement device with three position-sensitive detectors （PSD） was developed for an automatic spray height control system. We confirmed that the PSD could stably measure spray height outdoors using an infrared transmission filter. Then, the PSDs were evaluated for their output characteristics for leaves of major crops. Additionally, the interference areas of the PSDs were identified for optimal placement. Finally, the prototype was compared to an ultrasonic sensor in a potato field to evaluate its accuracy. The RMS of the device based on the ultrasonic sensor with a target spray height of about 60 cm was 5.5 cm. The developed device was useful as a sensor to measure the spray height.
