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.