http://www.atlasobscura.com/articles/australias-entire-gps-navigation-is-off-by-5-feet

Australia's Entire GPS Navigation is Off By 5 Feet And now they're
going to fix it.

Now, the Australian government has launched a project to update the datum
underpinning its satellite navigation coordinates, compensating for tectonic
shifts that have pushed everything on the continent about five feet over from
where it’s “supposed” to be.

The new datum will initially map to where the Australian continent will be
located in the year 2020 (hence the name). According to The Register, that means
when it first comes into use in 2017, it’ll be about 20 centimeters off. Then,
in 2020, phase 2 of the project starts and the project gets really interesting.
Phase 2 will synchronize the datum with GNSS, allowing “locations of points and
their movement over time to be modeled,” meaning the datum should be
continuously up-to-date.

Thanks to Ron Gleason.