Localization accuracy of a robot platform using indoor positioning methods in a realistic outdoor setting

Precise localization and reliable navigation are of crucial importance in order to fully automatize tasks in agriculture using field robots in an outdoor environment. However, under certain conditions, absolute localization accuracy of outdoor positioning systems, mainly global navigation satellite systems (GNSS), might drop under a critical threshold. Thus, field robots must rely on indoor positioning methods such as laser scanners and adaptive Monte Carlo localization (AMCL) in order to maintain necessary localization accuracy. Here, the localization accuracy of the field robot “Mathilda” using such an indoor positioning method is evaluated in a realistic scenario, in this case, an outdoor laboratory with plant pots aligned in rows. For this, the positioning error of the robot was determined using a motion capture system. The results showed a mean absolute distance error over all positions of 198.9 mm and a mean angular error over all positions of 4.9°. Most likely, limitations by the differential drive system, the large pneumatic tires, and unsatisfactory path planning are responsible for this large deviation.