When real time kinematics guidance first became available on agricultural global positioning systems in the mid-1990s, the price tag was $50,000 to $70,000.
It may have provided survey-grade accuracy, but the cost was prohibitive for prairie farmers.
Since then, prices have edged slightly downward, but within the past year the cost of RTK dropped dramatically. As a result, producers who have already come to appreciate normal GPS guidance are now looking closely at the sub-one-inch accurate RTK technology.
Base stations featuring the latest dual-frequency signals are now available from $13,000 to $20,000. Each base station can provide service to hundreds of implements, which makes station sharing a viable option.
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The RTK radio receiver, which adapts to an existing autosteer system, will cost $6,000 to $8,000 for each implement converted to RTK.
What’s behind this pricing trend and what do producers stand to gain?
When first introduced to prairie farmers, GPS was inextricably linked to precision farming and variable rate. Nobody thought of GPS any other way.
Precision farming had conceptual and technical problems in those days. The stuff didn’t do what it was supposed to, and even the experts weren’t sure exactly what it could do.
It was also expensive.
For a while, it looked like GPS might fade into farming history.
Outback was the first company to address these problems in a big way. It was the leader in terms of popularizing GPS that were affordable and user friendly.
When the company introduced its autosteer, it convinced farmers that GPS was no longer solely for the technologically savvy who wanted to master variable rate and precision farming. GPS might have a place on every farm.
Dwayne Hildebrandt has been with Outback since the first units were installed a decade ago.
“The explosion we saw in guidance units and autosteer is minor compared to what we’re about to see in high-accuracy RTK,” said Hildebrandt.
“We’re just beginning to scratch the surface of what can be done with high-accuracy, high-precision guidance. There’s a huge wave of demand for these services.”
Connor Rex, a GPS specialist with Enns Brothers John Deere dealerships in Manitoba, said the RTK trend is moving faster than he anticipated.
“When we first looked at RTK, we figured our customers would be the row croppers.”
He said these farmers need the repeatability they can get only with RTK, mainly because they want to repeat the same track over and over again for seeding, spraying, cultivation and harvest.
“But this year we’re finding more and more of the broad acreage grain farmers who were using WAAS and subscription guidance suddenly want RTK,” he said.
“They tell us they’ve already realized the benefits of regular autosteer, and now they want survey-grade RTK elevation accuracy, mainly for drainage work.”
Rex said autosteer is no longer considered a luxury on the farm. It has become a management tool that saves time and money as input costs continue to rise. Producers have learned that conventional GPS guidance helps increase profits by eliminating overlaps and skips,” he said.
“So RTK is the next logical step. When you sit down and do the numbers, most guys who need RTK get the payback on their investment in the first year.
“We’ve all seen the pricing come down in the past year. Two years ago, base stations were $20,000 to $25,000. But all the manufacturers – not just John Deere – are building and selling more RTK units.
“Demand and volume drives the price down. It’s just like laptop computers. A few years ago they were $5,000. Now they’re $500.”
Randy Gates, a member of the sales staff at Blight Equipment in Portage la Prairie, Man., said the ease of operation is an overlooked factor that’s prompting more farmers to get into RTK. A lot of producers were burned on the first generations of GPS equipment, and it left a bad taste, he added.
“A lot of guys used to have so much trouble making GPS work for them,” he said.
“They just got mad and said, ‘it’s all junk.’ Those are the hardest guys to sell to now. But they’re catching on. The systems have become so user friendly. You no longer need to be a computer geek to make GPS and RTK work for you.”
He said the price drop in RTK is a matter of higher demand from farmers along with closer competition among the main suppliers.
“It’s basically the same situation with any kind of electronic equipment,” Gates said.
“Back in 2003 when I worked for John Deere, an RTK tower was $35,000 to $40,000. Today, it can be a third of that price.”
However, it’s still expensive to put RTK into an implement.
“The unit on your tractor has only come down about five percent. I think that’s going to be the next big price breakthrough for farmers. The trend is that technology always becomes cheaper as more people adapt it.”
AutoFarm
Marty Cook at AutoFarm said broad acreage producers are among those adopting the new technology.
“A lot of guys are doing inter-row seeding now that they can have one-inch accuracy with their drills,” he said.
“You can put your anhydrous down in the fall and then come back in the spring and place your seed and the rest of your fertilizer two inches to the side.”
While this might sound positive, many experts caution that buying RTK just for the sake of having RTK is not a good decision. If there is an economic justification for high accuracy, the investment is a good one. If there’s no need for sub-inch accuracy, then why spend the money?
For those who decide to use the technology, antenna placement is a good place to start.
Cook said higher is always better in guidance.
As well, the wire running from the base station to the antenna is an important component that’s often ignored.
“Co-ax cable is good for a 50 foot high antenna,” he said.
“After that, too much of your signal is lost with co-ax. And 50 feet isn’t really high enough anyway.
“We use digital cable. That lets us go 200 feet up without any loss of signal strength or extra equipment.
“For drainage and elevation work, you need to put your tower in the field. If you mount it up on a (grain) elevator, your honest limit for good elevation work is about one mile from the elevator. If you put the station in the field, you should have excellent elevation accuracy.”
Cook said single frequency versus dual frequency RTK is another factor potential buyers should consider. He said many older RTK designs had only single frequency. When they lost their signal in the field, it might take 15 minutes or longer to pick it up again.
Dual frequency doesn’t provide better accuracy, but it does pick up the signal quickly before an implement has too much time to wander off course.
Cook said magnetic north versus true north is another consideration. RTK systems based on magnetic north always follow a curve, much like the correction lines in a north-south highway. Systems like AutoFarm use true north.
“True north always gives you a perfectly straight line. That’s the way to go. You don’t want extra curves built into your unit by the factory. For the best accuracy, you want your line to run perfectly straight.
“If you take an AutoFarm or Trimble into a field mapped with John Deere, you’ll run over your lines. And vice versa. That’s because AutoFarm and Trimble use true north.”
Cook said Australian grain growers already use RTK guidance on broad acre crops for inter-row seeding and better fertilizer use.
Cook said the next step in guidance is to steer the implement rather than the tractor.
CNH-Trimble
Gates said it’s unlikely a producer would move from zero steering guidance to full RTK.
“Most of my guys I deal with are experienced with GPS guidance. They’ve been on WAAS or subscription, and that’s fine for cultivation or harrowing, but now they want better accuracy.
“When you’re putting expensive seed and fertilizer down into the ground, you want a high degree of accuracy so nothing’s wasted.
“Same thing on the combine. If you can run a big, straight-cut header with one-inch accuracy from pass to pass, that means you get the entire crop in and you avoid overlap. That makes you money.”
He said all GPS guidance systems sold by CNH are 100 percent Trimble, whose RTK radio receivers cost $5,000 to $6,000. If a producer already has a compatible GPS guidance system and access to a base station, that investment is all that’s needed to move into RTK.
“But there are some brands of guidance systems that are proprietary. Our RTK doesn’t work with those systems.
“If you need a base station, the price now is down to $13,000. And if you do need to set up a full-blown RTK system from scratch, and you have no existing GPS guidance equipment, the price is now $25,000 to $28,000. That includes everything.”
Like most implement dealers, Blight is still in the early stages of its RTK program. Gates said the company recently installed a base station and tower at the Westrock Hutterite Colony near Portage la Prairie.
“That system went into service for this harvest. They were running straight cut headers. This fall, they’re going to be using it for anhydrous. We’ve also done a demo there with a 70 foot drill, showing how you can seed with one-inch accuracy.”
For elevation signals required in drainage programs, Gates said the CNH Trimble should provide sub-one-inch accuracy with two to three miles of the tower.
“We talked to a dealer down in Kansas, and they had farmers 22 miles from the base station getting three-inch steering accuracy. But it’s flat there. Very flat.”
John Deere Starfire RTK
Rex said the price of a base station and tower can be shared by farmers and other parties, such as a fertilizer dealer.
Enns Brothers has established a number of shared base stations in Manitoba and expect this will be the pattern of future RTK expansion.
“All the base station and tower do is transmit a signal, just like a regular radio station. There’s no limit to how many people pick up on that signal. All the data manipulation takes place in your GPS unit on your implement.”
Rex said that for safety reasons and accessibility, a grain elevator or a grain leg is preferable to a dedicated tower.
“An elevator or a leg is designed to have people working up there. The stairs are safe and there’s a platform.
“But if you set up a tower just for your system, you’ll probably have to hire an erection crew.
“And when it needs service, not very many people want to climb up a 150 foot tower, so that can mean hiring a professional climber.”
He said the shared base station his company set up in Portage la Prairie has the antenna about 200 feet in the air on top of the CanOat elevator.
The base station doesn’t need the height. It just needs to be mounted on a stable, solid footing with full view of the skyline and can be at ground level if necessary.
The antenna, on the other hand, should be as high as possible. Rex said 100 feet is considered the minimum height.
He said if a producer can work out a shared base station arrangement, he should be able to move into a single implement RTK operation for the receiver-only price of $8,000, or less if the implement already has GPS guidance.
This will not provide sub-inch elevation accuracy unless the implement is working on drainage within two miles of the tower, he added. It will, however, provide sub-inch steering 12 miles from the tower.
The shared base station partnership arrangements set up by Enns Brothers are generally spread over a three year period to cover the original investment plus maintenance during that time.
“But not everyone is happy with a shared base station,” Rex said.
“If you’re doing a lot of drainage work and you want sub-inch accuracy, the field where you’re running the drainage program needs to be within two miles of the base station.”
As for steering, some producers have sub-inch accuracy beyond the 12-mile limit. However, trees, hills, tall elevators and other line-of-sight obstacles can disrupt the signal.
However, line of sight isn’t the only limiting factor in the equation. Time is also an important factor. Radio signals are not instantaneous and take time to move through the air.
“You have to keep in mind that as you move further from the tower, your accuracy degrades on a gradual basis. It becomes slower because of the time factor in the signal.”
Outback
Hildebrandt said his company’s baseline RTK is a single frequency system that installs at the edge of a field.
It will be replaced by the new dual-frequency Eclipse RTK near the end of 2009.
“Eclipse will be compatible with what we already have. However, our E-Drive is not designed to take full advantage of either single-frequency or dual-frequency RTK, so we need to see improved steering controls.”
He said prairie farmers should be concerned about the lack of towers.
“In the States, they have towers everywhere. Some are privately owned. Others are government owned. But everybody has access to good strong signals.
“When Western Canada catches up in terms of tower numbers, RTK will really take off in terms of the service it provides.”
For more information, call Connor Rex at 204-782-7685, Marty Cook at 204-801-3603, Randy Gates at 204-745-7653 or Dwayne Hildebrandt at 204-896-2473.
