Leap second not a problem unless you are harvesting at the time

An extra second being added to the world clock in the New Year could have implications for farmers using GPS-controlled equipment at the precise time of the change.

On New Year's Day this year, the International Earth Rotation and Reference System Service will add one extra second to the world clock.

Sean Metcalfe, customer support manager with precision technology company Topcon, said the change would largely go unnoticed.

"Leap seconds are occasionally needed to keep the UTC [Universal Coordinated Time] coordinated to keep it in sync with the earth's rotation," he said.

He said it happened in October last year, and this year it is happening on December 31.

The Universal Coordinated Time clock will officially read 23:59:60 on December 31, so the added second is set to take place in Australia in the morning of January 1 at 10:59:60 (AEDT).

Consider not using GPS at the time

While seemingly harmless, this added second can indeed have impacts on the nation's farmers if they are using GPS navigation at the precise time.

Mr Metcalfe said the change could have implications for farming equipment and systems using the global navigation satellite service such as the tractors of GPS-guided headers.

"If you are operating the system in between the hours of 9:30am and 1:00pm [AEDT] you will find the GPS correction will drop," Mr Metcalfe said.

"You have two choices: you either do not use it during this time, or if you really need to use it, it is best to have the Glonass — which are the Russian Satellites — disabled."

Mr Metcalfe said normally it would not be an issue, but people were a bit more concerned this year as it was happening on December 31, in the middle of grain harvest, and people were worried there would not be support staff around to help them.

But he said people did not worry as the change happened often.

"It happens once a year sometimes and most people wouldn't even notice that it has happened, so keeping that in mind there is really no need for any fear."

And wait, there is more

Thanks to continental drift, Australia is also moving north by about seven centimetres every year.

This means in January a team of scientists will recalculate the nation's latitude and longitude coordinates.

Dan Jaksa from Geoscience Australia said this would improve accuracy of all spatial information across the nation, for things such as navigation, surveying, and transport.

He said the latitude and longitude in Australia were fixed to the continent, but the GPS systems were operating on a modern earth-centred system that were not fixed to Australia.

He said as the continent shifted so did the coordinates, but the centralised global GPS did not.

Because of this movement Australia has to deliberately change the GPS measurements to make it fit better to the global positioning systems.

But Mr Jaksa said farmers and machinery operators would not notice much in the change.

He said, if anything, they would not need to recalibrate their position as much.

"It will actually make the positions of driverless trucks in mining sites or driverless tractors in systems in agricultural regions far more accurate," he said.