Since the beginning of the 20th century, the growing demands for more food forced farmers to adopt resource-intensive and unsustainable practices, which increased both economic and environmental costs.
By the mid-1990s, new techniques were developed to make agricultural practices more efficient. A central objective was to increase yields and productivity while optimising the use of resources and reducing the negative impacts of intensive farming on the environment. These techniques are generally referred to as “precision farming”.
Precision farming is a technique that allows farmers to better allocate inputs (e.g. seeds and fertilisers) to specific cropland areas based on soil type, fertility levels and other characteristics of that site. Basically, precision farming incorporates four technologies: remote sensing, geographic information systems, positioning systems and process control.
GPS rapidly became the reference positioning system for the first applications used for precision agriculture: the service was free of charge, GPS accuracy was sufficient for applications such as yield mapping or variable rate pesticide application, and furthermore, it was particularly well adapted to the large agricultural fields found in the US.
However, the implementation of these techniques in Europe has highlighted the limitations of GPS for precision farming. Field size is ten times smaller on average than in the US requiring more accurate navigation. The emergence of new needs, such as automated planting and harvesting techniques, also requires more precise measurements. Consumer demands for organic foods and environmental protection have led to a need to reduce chemical use in this domain.
The main limitations of GPS relate to static accuracy and pass-to-pass accuracy (also called repeatability). Pass-to-pass accuracy refers to how far off equipment is from overlapping one pass of a field to the next, regardless of which pass it is on. Higher accuracy is especially important for mechanical weeding, for example, to reduce chemical use.
The EGNOS solution
In order to overcome the limitations of GPS, manufacturers of precision agriculture systems have integrated satellite-based augmentation systems (SBAS) to correct GPS measurements. EGNOS, the European contribution to global SBAS coverage, offers farmers a free service, available across Europe, which increases both GPS accuracy and repeatability. EGNOS post-processing techniques can achieve accuracy to within 20 centimetres in a few minutes.
Thus, EGNOS enables farmers to automate many tasks in the production cycle and maximize yields while at the same time reduce their impact on the environment.