The client works with automation systems for precision agriculture. The device is installed on tractors and helps apply agricultural inputs according to the vehicle’s position within the field.

The tractor is still driven normally by the operator. The embedded system uses a Linux display, field maps and predefined agronomic data to control the valves that apply fertilizer or crop protection products.

Based on the tractor’s position, the system determines the dose needed for each area of the field and controls the application locally.

For this concept to work, the position has to be reliable. An error of just a few meters can mean applying product in the wrong area. In this project, the challenge was to bring that error down to a few centimeters.

When a high-precision GNSS is still not enough

The client was already using high-precision GNSS receivers, but real-world performance on the tractor did not match expectations.

The problem was not only the receiver or the antenna. The agricultural vehicle had many sources of electromagnetic interference capable of degrading RF reception.

Motors, actuators, converters, switching power supplies, digital interfaces, cables and the device’s own electronics could all introduce noise into an application that depends on receiving extremely weak satellite signals.

So simply replacing the GNSS module with a better component would not solve the problem.

ECK’s job was to analyze the system as a whole and identify where the electronic architecture was hurting reception.

RF reception and centimeter-level positioning

The goal was a positioning solution suited to precision agriculture, with error small enough for the system to correctly distinguish the different application strips and zones.

The consulting work covered the antenna, the RF path, the power supply, grounding and component placement within the device.

Internal noise sources that could couple interference into the GNSS receiver or the antenna cabling were also evaluated.

The final result achieved centimeter-level accuracy, a necessary condition for valve control to be consistent with the agronomic map used by the system.

Board redesign to separate RF from the main electronics

One of the most important parts of the work was reviewing the printed circuit board architecture.

The GNSS reception section had to be treated differently from the main digital electronics.

Component placement, current return paths, ground planes, routing, power supply and board areas capable of generating or picking up interference were all analyzed.

The architecture was redesigned to increase separation between the RF section and the digital and power circuits.

Instead of concentrating everything in a single electrically noisy area, the GNSS section was isolated from the main electronics and connected through a suitable cabling solution.

This separation reduced noise coupling and improved signal reception.

Grounding is part of RF design too

In high-precision GNSS systems, grounding cannot be treated as just an ordinary electrical connection.

How returns are distributed across the board, and how modules, shields, cables and the mechanical structure are connected, directly affects the electromagnetic behavior of the assembly.

During the consulting work, different grounding and isolation strategies were evaluated to reduce unwanted currents and keep noise from other parts of the system from reaching the receiver stage.

This was particularly important because the device had to operate on a tractor, a far harsher electromagnetic environment than a lab bench.

GNSS receiver cabling and isolation

The path between the antenna, the receiver and the main electronics also received special attention.

An inadequate cabling solution can act as a coupling path for noise or degrade the signal received by the antenna.

So the redesign considered not only the board, but also how the different modules would be interconnected.

The goal was to keep the RF section physically and electrically separated from the main sources of interference, preserving signal integrity from the antenna to the receiver.

Precision agriculture depends on positioning quality

The system uses the tractor’s position to decide where and how much input to apply.

Before operation, the field is mapped and analyzed by specialists, who define the needs of each area.

During field work, the device continuously compares the GNSS position with this map and controls the application valves.

As a result, different areas can receive different doses of fertilizer or crop protection product according to the predefined needs.

In this type of application, a positioning error is not just a map error. It can result in double application, missed application or the wrong dose in a given area.

From prototype to thousands of units a month

After the architecture changes and the improvement in GNSS performance, the product reached the accuracy its application required.

The device was industrialized and has been in production for several years.

Today the system sells in volumes on the order of thousands of units a month, showing that the decisions made during the redesign were not limited to a lab prototype.

The solution had to be technically robust and also suitable for series production.

GNSS system consulting is more than choosing a receiver

This project shows that GNSS performance does not depend only on the specifications of the module used.

Antenna, power supply, PCB, grounding, layout, shielding, cabling and interference sources are all part of the same problem.

In applications that demand high accuracy, especially in environments with motors, switching power supplies and power systems, each of these decisions can determine whether the receiver delivers the expected performance.

ECK’s GNSS system consulting worked exactly on this point: turning a high-precision receiver into a system able to maintain that precision once installed in the real equipment.

Learn more about ECK’s electronic engineering consulting.