TABLE OF CONTENTS The ability of DGPS to provide real-time submeter- or even decimeter-level accuracy has revolutionized the agricultural industry [3, 4]. GPS applications in precision farming include soil sample collection, chemical applications control, and harvest yield monitors (Figure 10.3).
When collecting soil samples, GPS is used to precisely locate the sample points from a predefined grid (Figure 10.3). After testing the soil samples, information such as nitrogen and organic material contents can be obtained. This type of information is mapped and used as a reference to guide farmers in efficiently and economically treating soil problems.
When GPS is integrated with an aerial guidance system, the field sprayer can be guided through a moving map display. Based on the sprayer's location, the system will apply the chemicals at the right spots, with minimal overlap, and automatically adjust their rate. This, in addition to increasing productivity, ensures that chemicals and fuel are used efficiently.
GPS is also used to map crop yields. As the DGPS-equipped harvester moves across the field, yield rates are recorded along with DGPS-derived positions. This information is then mapped to show the yield rate.
Easy-to-use integrated systems with only a few buttons are now available on the market. DGPS corrections are available from the government-operated DGPS/beacon service free of charge, as well as from a number of commercial services. The user's own base station may be built as well (Figure 10.3).
