Autosteer systems have become part of everyday life on many farms running modern tractors. Here we show what’s involved in getting an old classic kitted out for auto-steer and ISObus connectivity

More and more tractors are leaving the factory auto-steer ready, so you only need to add a receiver and task controller to make the system fully operational. With these systems the steering is controlled by a hydraulic valve, and they rely on the operator terminal to be the interface. However, in 1994, when our AgroStar 6.21 first landed on farm, auto guidance was very much in its infancy.

Solutions for older tractors

For our classic project we recruited Vantage Agrometius, which distributes and installs Trimble auto guidance systems in Germany and the Benelux countries. In principle, auto guidance can be retrofitted to any tractor that has full- or assisted-hydraulic steering. But rather than fit a fully integrated system using
a hydraulic valve, we opted for a compact wheel motor below the steering wheel that
is quiet and maintenance-free.

Thanks to the integrated steering angle sensor, the system manages to keep the tractor on track going forwards and backwards as long as the speed is over 500m/hr. If you add a separate angle sensor on the front axle, the system will still be precise at speeds as low as 70m/hr.

The GFX750 display and the Nav 900 (which acts as both the receiver and controller) also form part of the package. Popping a 1GB data SIM card into the modem allows you to use the mobile radio RTK signal. In addition to the RTK correction data, jobs, waylines or application maps can also be received by the
small GX450 mobile radio modem.

Another benefit is the ISObus harness that can be connected to the GFX display. This can be utilised to control AEF-compliant ISObus machines and the likes of section control on a sprayer.

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