Global Positioning Systems (GPS) are satellite-based navigation systems that utilize a network of earth orbiting satellites. GPS operates well under any weather condition and does not require a subscription fee. GPS is a crucial component of precision agriculture by providing precise location information with very high repeatability.
In recent years, GPS have improved in their level of performance and functionality in part because new GPS receivers can track satellites not only from the 32 NAVSTAR satellites of the United States but also from the Russian GLONASS (approximately 24 satellites) systems. These high-accuracy navigation and positioning technologies are categorized as a GNSS (Global Navigation Satellite System). We anticipate that even higher levels of performance will be achieved when the Galileo satellite constellation (European Union) becomes available in 2014 with an initial operating capacity of 18 satellites and expanding to 30 satellites by the year 2020. The changing technology motivates the need for precise definitions.
It is clear that GPS will continue to have a remarkable impact on production agriculture. Vehicle guidance or automatic steering control has been the most commonly adopted GPS technology among growers in the last five years. Every year new and improved navigation systems become available with a range of precision capacities to fit most mechanical operations and with new functional capabilities. This publication describes the latest trends in GPS technology and elaborates on topics of extra functionality such as variable rate application, land leveling, and yield monitoring; all are now available from the cab mounted display interface.