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Australia's Entire GPS Navigation Is Off by 5 Feet

24 points| ghosh | 9 years ago |atlasobscura.com | reply

19 comments

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[+] ungzd|9 years ago|reply
But GPS is using WGS84 datum (usually). And they're changing their own local datum. Nothing will be changed for GPS. It will still use WGS84.

Or there are weird Australian upside-down phones and navigators where GPS calculates position in their local datum?

[+] tfm|9 years ago|reply
Official local datum is GDA94, which is usually within about a metre of WGS84. /me pats pocket protector

I think the idea here though is that the underlying terrain has scooted around a bit in the last twenty years, so a new datum would save on the need to print new maps and update the databases containing trig points and such. New coordinates can be labelled as explicitly aligned to the new datum, get some versioning happening.

Unfortuately it seems impossible to confirm this, because the Geoscience Australia website does not appear to make any reference to this purported new effort that's been making the rounds of late. New website layout, maybe their CMS is broken.

[+] abhikandoi2000|9 years ago|reply
"“We’re fast approaching the day when people will expect accuracies of centimeters in real time out of their handheld devices and then we’ll see a lot of head scratching as things no longer line up,” Smith told Scientific American three years ago. It looks like that day has arrived"

Has that day really arrived?

I doubt, given the fact that most consumer navigation systems are reliable (directions on Google Maps, pick up on Uber and alike) as long as they are not being blocked by major hurdles.

[+] rburhum|9 years ago|reply
Think AR applications. Anything that requires accuracy that is not a "Pokemon Go" game would need that.
[+] ChrisFoster|9 years ago|reply
Ugh, all the recent articles I've seen on this are subtly or entirely wrong about the reasons for a datum change (though this article is a lot better than most).

It's possible to account and correct for most of the 1.5 meters when transforming between GDA94 (the current Australian national datum) and ITRF2008 (effectively what's used by GPS), and the transformation published by Geoscience Australia is particularly simple, having only 14 parameters.

If you want to know about this from a reliable source, the ICSM site is the place to go. They actually know what they're talking about, and their faq in particular explains a lot of points of jargon and convention rather clearly: http://www.icsm.gov.au/gda2020/faqs-2.html

[+] avs733|9 years ago|reply
and shifting about 7cm per year. I did the math last night and realized that Australia has moved further than I am tall since my birth. For some reason that messed with my head.
[+] jacquesm|9 years ago|reply
Wait until it shifts underneath you while you're standing on it and see how that messes with your head. The first time I experienced a very minor earthquake the feeling did not leave me for weeks.
[+] Klathmon|9 years ago|reply
The thought that the ground we stand on grows more than we do is weird...
[+] anotheryou|9 years ago|reply
I wonder if google maps and OSM will be more accurate before or after the change. (I guess after, be because the maps are probably based on satellite images)
[+] maxerickson|9 years ago|reply
It depends on how that imagery has been rectified. If they were aligned to match up with the previous system, then any info derived from them would show the offset.