Machine automation using RTK GPS positioning

Machine automation is a challenging application that demands real-time positioning at the centimeter-level accuracy for precise jobs in the open fields. This positioning accuracy can be obtained by using a Global Positioning System (GPS) and employing a single reference station or through utilizing the service of a network of multiple reference stations. The paper first addresses the principles of the RTK positioning from a single reference station and next from a network. The potential of integrating the RTK positioning system and GIS to increase efficiency for machine automation in are explored. Such integration is proposed for implementation in a Supervisory Control and Data Acquisition (SCADA) system. The functionality and process automation of the proposed integrated system are discussed. The logical sequence of the soft PLC process program is illustrated. Two scenarios are presented for field machine automation to precisely operate according to previously preset plans. In addition, an efficient architecture of the integrated system is proposed. To evaluate the obtainable positioning precision when the system is mounted on machines, the RTK system was tested first when using a single reference station and next when using a RTK network. Results show that the system was successful in almost all time to achieve the target positioning precision at the cm level.