How do auto guide systems work?

Although the number of farmers who use the guided and self-guided systems is increasing and to some extent such systems are already a habit for most of them, there are still smaller or larger farms that still don’t use these precision farming systems.

One of the main reasons behind this is a lack of understanding of technology. Although the way actually this GPS or satellite self-guided system works is very complex and very important to get used with the technology, I would’t like to go further into it, because usually, to be able to use a car, one doesn‘t  need to know how the combustion engine works in detail or a gearbox  for example.

But to understand how such equipment works, we could take a look at the main component parts, what and how they do.

Thus, a auto guide system is composed of three main components:

the guidance monitor

satellite receiver (or antenna)

self-guidance system

Let’s have a close look and see what is the role of each component.

The guidance monitor

The main purpose of the guidance monitor is to provide an interface between the guidance system and the human operator. Today, most guidance monitors have color touch screens with interfaces that are also used by mobile phones to be easily operated even by inexperienced operators. Using a graphical interface, the operator enters commands for the self-driving system, sees the work results, inputs or outputs various data and information, performs various settings, and so on.

Modern monitors often have ISOBUS capabilities. In this way, implements attached to the tractor that are ISOBUS compatible can be automatically controlled by the guidance monitor (for example by automatically setting or changing the dose or by automatically closing and opening the working sections). One such monitor from the Trimble range is the GFX-750 model, which is also the manufacturer’s best-selling model.

Satellite receiver

The satellite receiver, or popularly called the antenna, is the device through which the guidance or auto-guidance equipment receives signals from global positioning satellites. You should know that most of the time, this receiver can get signals from several constellations of satellites, among the most used are GPS, GLONASS, Galileo and BeiDou. You should also note that the system only receives information from the satellites and does not transmit information (that’s why it’s called a receiver).

In addition to the basic function, previously described, the satellite receiver can perform other tasks such as:

✅ sending commands to the self-guiding system or to the tractor

✅may contain an assembly of accelerometers and gyroscopes to make corrections when working in sloping terrain (tilt compensation)

✅can process certain data sets that it transmits to various equipment or sensors or to the guidance monitor

There are situations where the previously described guidance monitor is integrated into the monitor where we also have tractor functions and information, but the satellite receiver is always independent.

Trimble’s top performing satellite receiver is the NAV-900, which performs all of the above plus some smaller ones we don’t need to mention. It can be used with any monitor in Trimble’s GFX range, including the GFX-350.

Auto guidance system

Only the monitor and the satellite receiver can be used for guidance, but in this case we are talking about (manual) guidance, where it is necessary for the operator to steer the machine on the furrow. But this type of guidance is becoming less and less used by farmers, most of them using a self-guided system, where the turns are also made automatically. And this is where the self-driving system comes in.

When we talk about agricultural machinery and self-driving systems, the former are divided into two categories:

• without factory preparation (pre-equipment) for self-driving (especially old machines)
• with factory preparation (pre-equipment) for self-driving (most machines of recent manufacture are like this)

In the case of a vehicle without pre-equipment, one of the solutions is the installation of the hydraulic steering system automatically controlled by the GPS system. But for several years, the second option, which is the installation of an electric servomotor instead of the tractor’s steering wheel, is increasingly used, due to the many advantages it comes with. The EZ-Pilot Pro system from Trimble has the advantages of ease of use, affordable price, excellent performance, but also the fact that it can be moved from one machine to another.

If the vehicle is pre-equipped for self-driving, this means that it already has the hydraulic systems for automatic steering control installed, as well as the necessary sensors. In this situation, in addition to the monitor and satellite receiver, only cables are needed for the connection between the self-driving system and the CAN network of the agricultural machinery.

Surely now it’s a little clearer to you how a self-driving system works, but to answer your more complex questions, which you certainly haven’t found an answer there, please contact us.