The vehicle's driver is not having to concentrate hard for hours on steering
Farmers are using combine harvesters with 'satnav' to make the most of good weather as they bring in the harvest.
The GPS technology makes it easy for the machines to keep working in the fields through the night.
The technology can also help map which parts of a field yield the best crop, to allow fertilisers to be targeted precisely where they are needed, cutting the costs and environmental impacts of farming, according to farmers.
The NFU believes technological advances can help meet the demand by the Government for farmers to produce more while having a lower impact on the environment.
Clive Blacker, an arable farmer from the Vale of York, says: "The GPS is very similar to a satnav system in the car but we're able to integrate it precisely with the steering.
"Instead of telling us not to turn left or right the GPS helps set out a path across the field, and travels up and down with a degree of accuracy of up to 2cm to ensure the most efficient harvesting or sowing of the crop."
GPS in the cab enables harvesting without the need for daylight
The global positioning system in agricultural vehicles and automatic steering enables harvesting without the need for daylight, and will also help farmers get their winter crops in the ground as the nights draw in during the autumn.
The system means the vehicle's driver is not having to concentrate hard for hours on steering the combine harvester.
The technology also enables the farmer to measure and map exactly which part of the field is reaping the best yield, analysis which can then be used to target problems in those areas.
Mr Blacker says such precision could allow the targeting of fertilisers and other inputs, and prevent run-off of excess chemicals into the local environment:
"It can reduce the inputs and it's a win-win situation, both environmentally and profitably, for the farmer. In the future, machines could play an even bigger part in our agricultural systems. In 10 years' time, you could deliver micrograms of chemicals with little robots going up and down the field."
He says the robots would be able to target the chemicals on the crops much more efficiently, reducing the use of chemicals significantly.