In 1999 Global Positioning System or GPS was first used on our farm. The Trimble Ag 170 Field Computer and AgGPS 124 DGPS reciever provided sub-meter field guidance, data logging and field mapping capabilities. Paired with Parallel Swathing and lightbar the field computer's graphical display allowed an operator to visually map previous passes and mark next adjacent pass for the most optimum trip across the field from pass to pass. This minimized overlap in sprayer applications and tillage passes. Planting and fertilizer operations took advantage of the data logging and GPS capabilities to log interior and exterior boundaries along with irrigation circles to create our first variable rate prescription maps for product application.
In 2002, Knuth Farms purchased the John Deere Auto Trac SF2. Along with the data logging and field mapping, Auto Trac added Auto Steer to our GPS capabilities. Auto Trac SF2 steers a machine for the operator through a field at the level of +/- 4" accuracy within a 15 minute time frame. The value of Auto Trac is realized in increased productivity in the form of faster speeds in difficult passes such as with contours and curves. Reduced overlap minimizing fuel and product use and reduced operator fatigue allowing for longer field time.
In 2007 and 2008 Knuth Farms achieved sub-inch repeatable accuracy through the purchase of John Deere's StarFire RTK technology. RTK is a highly accurate GPS signal enabling 1" repeatable accuracy making it possible to map applied products such as fertilizer within a field and then return hours, weeks or months later to the same location/path to place the seed in the fertilized zone. RTK utilizes a local, ground-based reference station, "base station" to transmit a highly accurate correction signal to the vehical's StarFire receiver via RTK radios. The "Fixed" location of the base station provides the reference point for repeatability year after year.
To complete the goal of sub-inch accuracy, Knuth Farms also purchased John Deere Swath Control Pro for the sprayer and John Deere Row Command for the planter for automatic section and row unit shut off capability. Based on GPS positioning, row units and implement sections automatically shut off in locations product had been previously applied to, effectively reducing doubling up on product in headlands, terraced and odd shaped fields.
In 2009, Knuth Farms purchased a Limited Production Build of John Deere's implement guidance system: iGuide. iGuide is the next level of performance in the John Deere Auto Trac system. iGuide consist of a GPS antenna and receiver mounted on the implement being pulled through the field in addition to the GPS receiver and antenna on the tractor. It actively shifts the tractor's path to correct tracking errors like implement drift or "roll" on sidehills, side to side shifts in variable soil types and curve following errors. Active Implement steering compensates for the deviation or "displacement" of the tractor's antenna from the geographical coordinates of the predetermined path such as when a tractor leans on side hills or when varying soil conditions create a side to side pulling action.