Development of a custom-built RTK-GNSS positioning system for agricultural operations
University of Helsinki, Faculty of Agriculture and Forestry, Department of Agricultural Sciences, Koetilantie 5, FI000790 Helsinki, Finland
*Correspondence: antti.lajunen@helsinki.fi
Abstract:
The
objective of this research is to assess positioning accuracy of a custom-built
RTK (Real Time Kinematic) base station. Setting up a RTK base station with
open-source tools is rather straightforward process requiring only few
components and basic programming skills. The base station and receiver unit
were developed by using a SparkFun GPS-RTK2 Board with
U-Blox ZED-F9P module. The board was paired with U-blox Multi band GNSS (Global
Navigation Satellite System) antenna. The board can use GNSS satellite signals
from Galileo, BeiDou, Glonass and GPS systems. The positioning accuracy was
evaluated in a fixed position and during operations in agricultural fields. The
RTK correction signal was used in connection with soil scanning measurements in
different crop fields of the Viikki Research Farm of the University of
Helsinki. For accuracy assessment, comparative measurements were carried out
with a commercial network RTK (NRTK) correction signal. The vertical and
horizontal accuracy of the positioning signal were evaluated based on the
accuracy variables calculated by the receiver. The vertical accuracy was also
evaluated by mapping the scanned trajectories on the height map which was obtained
from NSL (National Land Survey of Finland) open map data service. The
custom-built RTK positioning system accuracy was considered generally precise
enough for autonomous field work, but the reliability of the observed accuracy
should be confirmed with more extensive measurements. The commercial NRTK
signal accuracy was considered very good and reliable also for the vertical
direction.
Key words:
positioning accuracy, precision farming, real time kinematics, RTK-station, satellite navigation