Growing among the many options for GNSS corrections open to precision agriculture operators are tiered precise point positioning (PPP) services. Agriculture has had integrated GPS, and now GNSS, for decades. Ranging from individual RTK bases, networks of RTK bases and network RTK (RTN) to dedicated L-band satellite-delivered PPP, operators have been able to receive and apply the appropriate corrections for different crops and applications, from centimeters to meters.
Part of the appeal of such services, particularly for large agricultural concerns with mixed crops and operations, is having the full flexibility of tiered precisions. Additionally, near-global coverage has increased utilization.
“Specialty and high value crops require high accuracy,” said Michael Helling, senior director of strategy for Trimble’s autonomy group. “For instance, when drip tape is laid for fruits and vegetables, you would not want subsequent activities to be off more than an inch or so, to avoid cutting it. This is where RTK was essential, and a base was often set up, or an RTN accessed. But the RTX [Trimble’s PPP delivered by L-band satellites] high-precision option, CenterPoint RTX, easily meets those needs.”
Like some other PPP correction services, Trimble’s RTX also has lower precision subscription options: RangePoint for 15 cm and ViewPoint for 30 cm pass-to-pass accuracy. These services are also utilized outside of agriculture. For example, CenterPoint, delivering centimeter precision, is utilized for certain surveying and construction applications and FieldPoint for asset mapping. Trimble has also developed embedded solutions, based on the same core technology for, among other things, maritime, robotics, autonomous vehicle, and assisted driving applications.
Certainly many agriculture applications can suffice with lower precisions, such as broadacre crops, where there may be no need to maintain row-to-row and year-to-year repeatability. Where some amount of overlap between passes is acceptable, coarse navigation at sub-meter to meter precision may be all that is needed. However, as Helling notes, precision becomes addictive, and as the field equipment becomes more capable of positionally topical functions, many operators are stepping up in levels of precision.
“Farmers are more precisely testing fields with all kinds of sensors and seeing where the field actually differs in soil and nutrient content,” said Helling. “There are different approaches and value propositions. One is saying I need to fertilize this area better so that I can get a better yield. There are also situations where a specific area of the field might only produce to a certain level. Farmers can pinpoint where those areas are to apply fertilizers so as not to waste it and optimize their bottom line.”
For many agriculture applications, the reality is that you have a tractor pulling some other piece of equipment through a field.
“Think about sprayers, forever behind a tractor,” said Helling. “Our equipment can control a lot of things around the rate, precisely targeting specific pieces of a field or row. When you start thinking about sustainability, being able to turn the spray on and off where you’ve already sprayed, you can avoid overspray.”
Sensor integration helps automate the process.
“We just aquired a company in France called Bilberry; their technology is very effective at identifying weeds. You can identify what’s in the field and can decide how you’re going to treat it. The next immediate steps in automation for agriculture might not be full autonomy, but more automation in the equipment that’s being pulled, and sensors that inform what they do.”
