Design of self-calibration method for sound-basedpositioning system in greenhouse

There is a promising potential to use sound-based positioning system as low cost platform for automation and robotic system in agriculture. It can provide high positioning accuracy with relatively low cost. For practical use, it is important to make deployment of this system become simple and easy. Therefore, self-calibration method is highly demanded to replace manual calibration which is laborious, impractical, and time consuming. Here, we proposed a self-calibration method for sound-based positioning system in greenhouse. Experiment and numerical simulation were conducted to evaluate the performance of the proposed method. Experimental result shows that by using the proposed method, calibration of the sound-based positioning system in 7 m x 16 m area can be done with relatively small error, about 2-5 cm. We also investigated the performance of the proposed method under different greenhouse conditions, to see the influence of wind and temperature. Although there are some limitations, this study shows the feasibility to use the proposed system in greenhouse or other places with relatively flat floor.