Evaluation of non-satellite self-navigation system and Comparison with GNSS receiver for optimal tractor routing

Site-specific agriculture is a subset of precision agriculture that aims to increase productivity as well as the quantity and quality of crops based on measuring spatial variation, soil and plant characteristics, and consumption of inputs as variables in time and space. The first step to fulfill this goal is to locate the agricultural machine in the relevant place so that the desired operation can be performed accordingly. In the current research, a ground positioning device with sensors for measuring the steering angle and the number of rotations of the moving wheel of the tractor has been developed. The system was field-tested with local positioning without needing external servers, and the data were compared with the output values of a GNSS receiver. The experiments were performed on asphalt, plowed and uncultivated fields as well as in sunny and cloudy conditions. The statistical design was based on randomized completeblocks as a factorial test in 2 × 2 × 3 with four replications. According to the obtained results, the X and Y axes data of the GNSS receiver and self-tracking device showed a significant difference at the 1% and 5% levels, respectively. Changes in environmental factors, including sunny/cloudy and the ground surface conditions on both the X and Y axes, did notsignificantly affect positioning by the GNSS receiver and the self-tracker. The accuracy of the tracker system in the X direction was found to be 25 cm and for the GNSS receiver 250 cm, while in the Y direction, this was 50 cm and 140 cm for the GNSS receiver. As a result, the tracker system was more accurate on both the X and Y axes. In addition, path deviation distances obtained with the GNSS receiver and the self-tracking device were significantly different at the 1% probability level. The accuracy of determining the distance in the selftracking system was 60 cm, while with the GNSS receiver, it was 400 cm. In general, the performance of the self-tracking system in finding the optimal trajectory was more accurate than the conventional GNSS receiver (without DC correction).