Satellite-based positioning systems for precision agriculture

Global Navigation Satellite System (GNSS), which includes the global positioning system (GPS), is a core enabling Precision Agriculture technology used to indicate real-time position of a vehicle as it moves across a field. Over the years, many different positioning technologies have been developed including placing mechanical furrow followers on vehicles, using dead reckoning, burying cables across a field, and placing radio frequency transponders at various locations around a field (Heraud and Lange, 2009). However, many of these technologies lacked the accuracy necessary for common field applications, and were impractical because they required either extensive installation of permanent equipment or systematic transfer of stationary equipment from one field to another. GNSS helps farmers overcome these limitations. In this chapter, readers are provided with a basic description of how GNSS technology works, the fundamental operating principles, common sources of error, and how different levels of accuracy are achieved through differential corrections.