Making the farmer beam

City dwellers often think wistfully of moving out to the green and pleasant countryside, where technology hasn’t yet dictated a highly competitive and frenetic pace of life. Think again. Twenty years ago, one man worked 200 acres of land on average, whereas now he works 500. The changed pace is often due to high technology and one example is something called precision farming.

The aim is to increase minimise costs and wastage by targeting resources such as labour, seed, fertiliser and pesticides as accurately as possible. Up until now the need to establish local reference stations and communications links to establish positioning may have limited the impact of precision farming as a practical option, but digital images from orbiting satellites are rapidly making it more viable. For example, by adding a harvest measurement device to a global positioning system on a combine harvester, the farmer can map yields electronically.

After the launch of the Italsat F2 communications satellite, Racal Survey has introduced a new differential GPS service called Landstar, which will give farmers positions accurate to one metre anywhere in Europe at any time of day and in any weather.

Users obtain basic positioning from the US operated constellation of GPS navigation satellites. Because of deliberate degradation applied by the US department of Defence to prevent its use for military purposes, conventional GPS is only accurate to around 100 metres, sufficient for general navigation perhaps, but not for a precision farming application.

A network of Racal reference stations around Europe are able to measure the deliberate errors applied to the GPS signals and calculate the amount by which they must be corrected to restore their accuracy. The Italsat satellite transmits the results of these calculations to Landstar users who only need use a small saucer sized antenna to receive the data.

With such systems in place, even the farmer may eventually be replaced by a machine. Back to the good life in the city!

Figure 1: Precision farming with Landstar DGPS positioning

{{Racal SurveyTel: New Malden (01344) 388062Enter 401}}