While the ability to harness the field navigation power of GPS has been around for decades, these days equipment makers are hitting new levels of accuracy and reliability and are trying to reach new users. They’re also tapping into the exciting developments in varied countries’ satellite programs.
International satellite constellations continue to evolve and aid in positioning availability. The U.S. (GPS) and Russia (GLONASS) have started launching new generation type satellites. When it’s operational, Europe’s Galileo system will offer yet another array of positioning signals. Progress on the trouble-plagued system is disappointing, though the European Space Agency (ESA) reported it planned to launch more satellites soon with another deployment due at the end of the year. Initial services will be made available by the end of 2016. As the constellation is built up beyond that, new services will be tested and made available, with system completion scheduled for 2020. China has announced it will complete the BeiDou constellation by 2020 as well.
Multiple systems also provide “better positioning around obstacles that may block the sky, not to mention improved location when inside a crop canopy, orchard or forest,” says Greg Guyette, owner of Insero.
Bottom line is volume matters, he says. The more satellites and systems operating, the more accurate a receiver can be, in the U.S. and worldwide. Using GLONASS-capable receivers right now, in particular, offers a significant benefit — but users need to ask their suppliers to make sure products can access the signals.
“Just because a vendor mentions RTK, prospective buyers may want to verify that the receiver is ‘dual frequency RTK,’” adds Mike Gomes, vice president of business development, Topcon Positioning Systems. Why? Accuracy and repeatability between single and dual frequency RTK can be significant.
Products, Levels Of Play
To review a few basics, necessary satellite signal corrections are available to users through a few primary sources: free federally operated systems (such as WAAS); subscription services from precision vendors; and RTK networks. RTK networks utilize multiple base stations to communicate corrections. They’ve been built by major manufacturers — access is purchased on a yearly basis — or built by state governments with free access.
These sources provide a variety of accuracy levels, from 10 cm (about four inches) to 2 cm (about 0.8 inch). Two-centimeter accuracy potentially has a much greater customer base than 10 cm, says Guyette. “Improvements and cost reductions in satellite broadcasts of high-precision signals and greater availability of networked base station and Internet solutions that give 2 cm accuracy should continue to grow,” he says, adding that groups like MyWayRTK, for instance, have been effective in bringing high-precision offerings to a large volume of diverse ag customers within the U.S.
Precision companies continue to offer a variety of innovations. Most recent developments have been around either multiple satellite constellation positioning or the correction sources for those signals, says Topcon’s Gomes. His company, for instance, has introduced its Topcon Hiper V base station which utilizes the company’s Vanguard chipset with 224 Universal channels — and the ability to receive and utilize signals from GPS, GLONASS, Galileo, QZSS and BeiDou satellite systems.
Topcon optimizes GNSS positioning with the help of other critical components in its new receiver, the AGI-4 receiver/steering controller. Here, the antenna, inertial sensors, digital compass and path planning engine all contribute to robust performance with repeatability.
Raven offers satellite and cellular delivery of both decimeter and RTK accuracy. The company’s new GPS receiver, the 600S, is going to be popular because it has such seamless integration with the company’s field computers and other systems, says Kristin Harms, marketing communications specialist. The unit comes with flexible subscription options affordably priced, she adds.
Even with better satellite systems and ground equipment, there are times when correction signals are temporarily lost. GPS equipment manufacturers have developed technology that “fills the gap,” such as with Ag Leader’s new StableLoc feature on its dual band GPS 6500 receiver. “When the signal is degraded, the receiver transitions to the next highest available correction source to allow for continued machine guidance. When the higher correction source becomes available again, StableLoc will transition back to the guidance line,” explains Sam Worley, product marketing specialist.
Ag Leader introduced the GPS 6500 and 6000 last year as well as its TerraStar subscription service, for use with the 6500. TerraStar offers 1.57-inch (4 cm) repeatable accuracy.
Back40Precision sells the Ag Leader GPS 6500 receiver — and Co-Founder Alison Hinton attests to its popularity, in part because of the unit’s “fast acquisition and significantly improved accuracy.” The company has also recently released its Back 40 RTKonnect, a Wi-Fi and Bluetooth-capable NTRIP client device that can replace the need for modems in most RTK applications. This enables farmers to use their smartphones or Wi-Fi hotspots without having to get a separate data plan.
All GPS technology firms PrecisionAg spoke with agreed about the need for a variety of technology options for precision adopters of all levels.
Hinton believes that precision is becoming more widely accepted due to diversifying product lines that allow for building onto an existing system in stages. “New users are more eager to adopt thanks to increased flexibility on selected equipment options and relative price points,” she says.
Raven’s Harms agrees: “As demand increases for using higher accuracy GPS in a variety of applications, it is important that we deliver a variety of options while making them easier for the customer to implement.”
John Deere’s StarFire 3000 receiver gives users a variety of technology options, via the company’s StarFire subscription service. Adopters can get into precision guidance at the comfort and accuracy level they need, from Parallel Tracking to the one-inch, repeatable accuracy of StarFire RTK. “The StarFire 3000 receiver grows with you,” says Barry Nelson, manager, media relations.
Trimble is seeking to attract different tiers of users with its subscription services. The company started by introducing CenterPoint RTX in 2011.
CenterPoint RTX delivers GPS/GNSS-enabled, repeatable 1.5 inch (3.8 cm) corrections via satellite directly to the built-in receiver in users’ existing Trimble displays. No base stations, additional radio hardware or cellular modems are needed. “Our engineers have come up with some pretty powerful breakthroughs in terms of how you can get centimeter accuracy from the sky, in a way that wasn’t possible before,” says Lisa Weatherbee, Trimble Positioning Services’ business area director for the Americas.
Even in the few years since the CenterPoint RTX introduction, the Trimble team has made improvements, including shortening field convergence time. “In North America and Europe, growers can turn on the tractor and get to work almost immediately,” explains T.J. Schulte, marketing manager, Trimble Agriculture Division. Trimble’s RTX technology is also used to help RTK users who might experience interruptions in their radio signals. With a feature called Trimble xFill, farmers can keep working through a brief RTK radio outage or loss of cellular connectivity.
While CenterPoint RTX has been well received in the market, he says the company wanted to attract growers who were not using any kind of high accuracy service. Trimble then introduced RangePoint RTX, a subscription service which offers half-meter accuracy (15 cm pass-to-pass) at a affordable price point.
“We’ve seen a lot of people go off using WAAS, for instance, and start taking advantage of better accuracy. They can start working their way up that accuracy curve,” says Schulte.
Steering systems launched the whole precision ag phenom years ago, and manufacturers have been developing many more vital ways to harness new GPS possibilities ever since.
One of the most powerful has been variable-rate application. The GNSS/GPS products that are getting the most attention and selling best are the simple logging and rate control devices that can be accessed through a cell phone (or mobile device), says Insero’s Guyette.
“Products like AgOtter allow a box to sit and record all GNSS/GPS and spray data all day every day. It can also control to a constant rate if wanted/needed. It has the ability to communicate with any Apple product — iPhone, iPad, iPod — and relay all data wirelessly with a button push,” he says. “The mobile device can be used as a real-time coverage map (and rate monitor) if the user wants, or a manager can simply put the monitor away and the box will record and control on its own — unseen and virtually unknown to the driver.”
Now GPS technology is starting to take off in planter and seeder control, adjusting populations — and ultimately, switching varieties — on the go.
Other new applications, such as control of irrigation systems, are also gaining traction. This new sector comes at a time when careful use and protection of water resources has gained national attention. GPS technologies are also being used in fleet management and field scouting.
Perhaps not surprisingly, manufacturers agreed that one of the biggest challenges they face ahead is how to use GPS more effectively to help dealers and growers collect, manage and evaluate data. Stay tuned.