Tractors have ground to a halt in paddocks across Australia and New Zealand because of a signal failure in the satellite farmers use to guide their GPS-enabled machinery, stopping them from planting their winter crop. ”He said the winter cropping period had kicked off with a perfectly timed autumn break — the first major rainfall event of the season that heralds the crops’ growth period — but the GPS outage would probably mean major costs and headaches for farmers. \\u201CMy crop sprayer relies on the GPS signal to tell the spray unit how much chemical to put on, where it is in the paddock and how many nozzles it needs working