Growers switch to expanding cellular GPS network for machine guidance

An expanding cellular RTK (real-time kinematics) differential GPS network in the WA agricultural region is attracting increased grower uptake for its improved accuracy, reliability and repeatability with machine guidance compared with existing systems.

The McIntosh & Son MNet cellular RTK network is heading towards its third harvest season this year and is expected to add another five reference station locations in the northern wheatbelt before headers start to roll.

About 20 locations already stretch from Geraldton, south-east to Ravensthorpe and down to Albany on the south coast.

McIntosh & Son precision farming regional manager Josh White said compared with RTK services that used radio frequencies, cellular RTK offered several benefits, including improved accuracy over longer distances, reduced delays from satellite convergence, automatic switching between reference stations, usability across more machines, and increased competitiveness.

“The MNet cellular RTK network can handle data from a full multi-constellation of satellites for high accuracy, whereas radio-based systems cannot pass the message over a greater distance,’’ Mr White said.

“There can also be the typical ‘blackout spots’ with radio RTK systems and delays while waiting for satellites to converge. Cellular networks also can have issues in low cellular areas, or perhaps when driving under trees, but it is not as significant. The satellite convergence time is almost instant.’’

He said when an RTK service within a paddock swaps between reference stations, this also could cause a “line skip’’ with radio systems, reducing accuracy out to 1m and by up to 3m, and requiring operators to re-mark their line.

With the McIntosh & Son MNet cellular network, the service automatically switches to the nearest reference station without any skip and, hence, maintains the highest accuracy.

Mr White said the fact the cellular RTK service was agnostic, allowing it to be used with multiple receiver or guidance screen platforms, was another big benefit and he anticipated this could soon be extended to John Deere systems.

“If a grower has a mixed fleet of machines, this means it can be used across all of the machines,” he said.

“The MNet RTK service is not specific to a machine. One farm licence gives access for five machines to be logged-on to the service at any one time, but it can be used across 10 machines if desired.’’

He said he believed the affordability of the cellular RTK service would further drive subscriptions with growers, particularly those looking to use it with multiple machines.

Near Wongan Hills, farmer Matt Sewell had been using a premium satellite service for 2cm GPS accuracy on the family’s ‘Stanhope Farms’ properties before subscribing to the McIntosh & Son cellular MNet RTK service about 12 months ago.

The Sewells use MNet with their New Holland header and tractor that tows their chaser bin, with a Challenger tractor that pulls their seeding rig and with a Miller Nitro sprayer. Up to three machines can be using the service simultaneously.

Mr Sewell said the previous satellite system was quite expensive, requiring four subscriptions for GPS guidance even though they were all in use only for about a one-month period.

He said the one farm licence with MNet was competitive and if they used the service across more machines, the payback on the subscription would be even quicker.

The cellular system also allowed for remote access and data transfer.

“With the air seeder, every time a job is finished, the data is automatically uploaded and I can access that and the (in-cab) monitor,’’ Mr Sewell said.

He said repeatability with the satellite system was good, but the MNet service was better and the acquisition of the correction signal now occurred within seconds.

“With the old system, the acquisition time can be up to 45 minutes, although this rarely happened,” he said.

“Previously, sometimes we couldn’t be bothered shutting the tractor down and then having to reacquire the signal.

“We can still have some areas where we lose the cellular correction, but in these situations, a timer comes on the monitor, giving you the correction for around another 20 minutes while it reacquires.”

At their ‘Lindum’ property near Carnamah, the Dring family have been using the McIntosh & Son cellular MNet RTK service during the past year with two John Deere tractors and their New Holland harvester.

“We are wanting to tramline here, so we were seeking an effective and accurate system and it is going well,’’ said Roger Dring.

“We are part of the way there with the tramlining and it’s a good system.’’

The family previously used John Deere GreenStar GPS guidance.