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Australia Has Moved 1.5 Metres, So It's Updating Its Location For Self-Driving Cars (cnet.com)
An anonymous reader shares a CNET report: Australia is changing from "down under" to "down under and across a bit". The country is shifting its longitude and latitude to fix a discrepancy with global satellite navigation systems. Government body Geoscience Australia is updating the Geocentric Datum of Australia, the country's national coordinate system, to bring it in line with international data. The reason Australia is slightly out of whack with global systems is that the country moves about 7 centimetres (2.75 inches) per year due to the shifting of tectonic plates. Since 1994, when the data was last recorded, that's added up to a misalignment of about a metre and a half. While that might not seem like much, various new technology requires location data to be pinpoint accurate. Self-driving cars, for example, must have infinitesimally precise location data to avoid accidents. Drones used for package delivery and driverless farming vehicles also require spot-on information.ABC has more details.
If it was the case we would be in deep trouble considering the typical error in GPS. That is the reason why other sensors like LIDAR and cameras are also used. GPS is for having a general clue where you are, and 1,5 m accuracy would be plenty for that.
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Already done. It's called Ground Based Augmentation System (GBAS).
http://www.faa.gov/about/offic...
There's also a system called WAAS, Wide Area Augmentation System, and others.
http://www.novatel.com/an-intr...
A short description (I know, TLDR...) is that ground-based transmitters broadcast an error signal - the difference between received data and the actual known surveyed position. Any properly-equipped receiver uses this signal to offset its GPS-measured position accordingly.
My Garmin GPS that I got back in 2005 used the WAAS system. It's been around for quite some time.
--Brandon / Split Infinity Music
http://www.unoosa.org/pdf/icg/2012/template/WGS_84.pdf
WGS84
Geoscience Australia, where I work, is implementing a updated but fixed Coordinate Reference System pegged at the year 2020 called Geodetic Datum of Austrlai (GDA2020) which removes drift error accumulated since GDA94, after which time a time component will be added to all coordinates so that GDA2020 will be the last update as the time component will cater for continued drift.
Also, imagine a line of people standing single-file, extending infinitely in both directions. There are, of course, an infinite number of people. Now, imagine each of these people is joined by a partner. Are there twice as many people now? Does this mean there are "2 x infinity" people? But surely you can't do that to infinity. Er...
Spoiler; I'm not a mathematician, and don't have the answers, I'm just throwing this out here for amusement. Though I guess someone who knows more about this than I do could explain it
Modern mathematics recognizes the existence of different "sizes" of infinity, but they don't follow the standard rules of arithmetic. The basic idea is not complicated: anyone who can grasp intermediate algebra should be able to understand it, eventually. (I'm sure that my explanation won't be good enough for a lot of people though; try searching YouTube for "Hillbert's Hotel paradox", maybe.)
However, the infinite is far outside our everyday experience, so a bit of vocabulary from higher math will make it a lot easier to discuss the examples which follow:
set - an unordered collection of unique elements. Elements can be numbers, names, other sets, or whatever. Duplicate elements are not allowed: the number 53 (for example) is either in a particular set, or it is not; the set cannot contain two "copies" of 53, or anything like that.
cardinality - this is the "size" of a set. Two sets have the same cardinality if and only if their members can be put in one-to-one correspondence. For sets with a finite number of elements, such as the set of letters in the English alphabet, the cardinality is simply the number of elements in the set: 26, in this case. This is easily proven by simply associating a number with each letter (A => 1, B => 2, C => 3, ...).
Where things get interesting, is when we try to compare the sizes of two infinite sets, such as the set of all even numbers (0, 2, 4, 6, ...) versus the set of all whole numbers (0, 1, 2, 3, 4, ...). We cannot simply count the number of elements using finite whole numbers. Instead, we must use transfinite cardinal numbers. To understand what those are, consider some classic examples:
Hillbert's Paradox of the Grand Hotel ...
Imagine that Hillbert's Hotel has an infinite number of rooms, every one of which is occupied by exactly one person. The rooms are each numbered with a sign on the door: 1, 2, 3, 4,
Question: A new guest arrives, and asks the host for a private room. Can the host provide him with a room without doubling anyone up, or kicking anyone out of the hotel?
Answer: Surprisingly, yes he can! Here's one way he could do so: the host gets on the public address system and instructs every guest to pack his bags, leave his room, look at the number on the door, add one to it, and move into the room with that new number. So, the guy in room #1 moves into #2, the guy in #2 moves into #3, and so on.
At a finite hotel, this could never work: whoever was in the last room would be kicked out, with no higher numbered room to move into. However, in Hillbert's infinite hotel there is no last room, and so there is no problem. Everyone moves over by one room, and the new guest moves into room #1.
Conclusion: infinity + 1 = infinity.
Question: Suppose that the neighbouring Cantor's Infinite Hotel (same setup) needs to be fumigated (or nuked from orbit) because it is infested with an infinite number of cockroaches. The manager of Cantor's Hotel asks the host of Hilbert's Hotel if he can temporarily accommodate an infinite crowd of additio