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EU Space Science

Galileo: Europe's Version of GPS Reaches Key Phase 328

Posted by Soulskill
from the not-yet-persecuted-by-the-catholic-church dept.
another random user sends this quote from the BBC: "The third and fourth spacecraft in Europe's satellite navigation system have gone into orbit. The pair were launched on a Russian Soyuz rocket from French Guiana. It is an important milestone for the multi-billion-euro project to create a European version of the U.S. Global Positioning System. With four satellites now in orbit — the first and second spacecraft were launched in 2011 — it becomes possible to test Galileo end-to-end. That is because a minimum of four satellites are required in the sky for a smartphone or vehicle to use their signals to calculate a positional fix."
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Galileo: Europe's Version of GPS Reaches Key Phase

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  • Good to hear (Score:5, Interesting)

    by Sycraft-fu (314770) on Saturday October 13, 2012 @10:20PM (#41646557)

    There has been far, far too many delays and political fuckery with this. I'm glad to hear it is finally going online.

    Satellite navigation is just very important to everything these days (it is the primary nav method for all planes, ships, etc). Having everything rely on GPS, and thus on the budget the US chooses to spend keeping it working, is not a good idea.

    This will make things much more reliable since, after an initial hissing match, the US and EU settled down and the systems play nice together and you'll be able to get devices that use both for better accuracy and reliability.

    • Re:Good to hear (Score:4, Insightful)

      by Grave (8234) <awalbert88NO@SPAMhotmail.com> on Saturday October 13, 2012 @10:33PM (#41646629)

      Oh, the budget for GPS will pretty much never be cut until the system becomes obsoleted by something newer. The US military relies on GPS. However, the more navigation systems we have, the faster and more reliable fixes can become for civilian use.

      • Re:Good to hear (Score:5, Informative)

        by FireFury03 (653718) <`slashdot' `at' `nexusuk.org'> on Sunday October 14, 2012 @03:15AM (#41647697) Homepage

        Oh, the budget for GPS will pretty much never be cut until the system becomes obsoleted by something newer. The US military relies on GPS. However, the more navigation systems we have, the faster and more reliable fixes can become for civilian use.

        ISTR that due to budget cuts the newer GPS satellites don't operate in polar orbits, giving poor coverage at the poles.

        • by Conley Index (957833) on Sunday October 14, 2012 @05:48AM (#41648237)

          ISTR that due to budget cuts the newer GPS satellites don't operate in polar orbits, giving poor coverage at the poles.

          Poor coverage at the poles is not a problem: If I can see the sky but no GPS satellite, I just have to figure out if there are polar bears or penguins around to know at which pole I am.

          • by peragrin (659227)

            It is simpler than that look for actual land.

            The north pole has none, the south pole you can't get to by water.

        • Re:Good to hear (Score:4, Informative)

          by DerekLyons (302214) <fairwater@gmFREEBSDail.com minus bsd> on Sunday October 14, 2012 @06:10AM (#41648297) Homepage

          ISTR that due to budget cuts the newer GPS satellites don't operate in polar orbits, giving poor coverage at the poles.

          You recall incorrectly - the GPS constellation has never had any birds in polar orbit, and has always provided poor coverage at very high latitudes.

          • Re:Good to hear (Score:5, Interesting)

            by heypete (60671) <pete@heypete.com> on Sunday October 14, 2012 @06:21AM (#41648329) Homepage

            You recall incorrectly - the GPS constellation has never had any birds in polar orbit, and has always provided poor coverage at very high latitudes.

            On a more detailed note, GPS satellites are in inclined orbits at 55 degrees. This means that a receiver at the pole would only ever see a satellite reach a maximum altitude of 55 degrees over the horizon.

            While is certainly isn't as great as at lower latitudes, it's more than adequate to provide location information -- it's not like the poles have huge buildings and whatnot that would obstruct the view. I wouldn't really consider that to be "poor" coverage, but your mileage may vary.

            The Russian GLONASS system has satellites in inclined orbits at 64.8 degrees as Russia is located at higher latitudes than the continental US. This can get proportionally better coverage at higher latitudes.

            Galileo is planned with a 56 degree inclination.

    • Re:Good to hear (Score:5, Interesting)

      by caseih (160668) on Saturday October 13, 2012 @11:18PM (#41646803)

      In agriculture GPS guidance systems already have the capability of talking to Galileo when it is finished, and Glonass right now. After the military, agriculture is probably the most dependent on positioning technology these days. If GPS guidance goes down (IE our hardware has a problem), we simply cannot drive the machines. They are too wide to drive manually (my sprayer is 120 feet wide-- very difficult to drive that manually at less than 5 feet overlap even with markers) and the inputs too expensive to waste on overlaps. If GPS fails, everyone can switch to Glonass with Glonass correction signals, which should keep us going, but Galileo would offer superior accuracy and also precision. Such a switch, however, is not instantaneous. Would take weeks or months to get the firmwares updated (though the radios already are capable). And if that failed, I guess we can do terrestial positioning signals.

      But it's not a matter of if GPS will fail. It's a matter of when. Maybe the US will be able to replace satellites when they die, but if not, it should be very interesting to see what happens.

      • GPS satellites are already being replaced. So far, three IIF sats have made it into orbit. As usual with US military operations, things happened late and extremely over budget, but things are happening and the chance that the system fails due to not enough operational sats is rather small.
      • In agriculture GPS guidance systems already have the capability of talking to Galileo when it is finished, and Glonass right now. After the military, agriculture is probably the most dependent on positioning technology these days. If GPS guidance goes down (IE our hardware has a problem), we simply cannot drive the machines. They are too wide to drive manually (my sprayer is 120 feet wide-- very difficult to drive that manually at less than 5 feet overlap even with markers) and the inputs too expensive to waste on overlaps. If GPS fails, everyone can switch to Glonass with Glonass correction signals, which should keep us going, but Galileo would offer superior accuracy and also precision. Such a switch, however, is not instantaneous. Would take weeks or months to get the firmwares updated (though the radios already are capable). And if that failed, I guess we can do terrestial positioning signals.

        But it's not a matter of if GPS will fail. It's a matter of when. Maybe the US will be able to replace satellites when they die, but if not, it should be very interesting to see what happens.

        If 5' of overlap in unacceptable, then Glonass will not help. The military signal provides 10 meter resolution, and the civilian signal provides one quarter of that (20 meter resolution - exercise to the reader why that is one-quarter resolution). In fact, I'm surprised that you can get consistent 5 foot accuracy with GPS. You might have more overlap than you think.

        • by profplump (309017)

          It's pretty common to use a localization signal in agricultural radio navigation to provide much greater accuracy than is available over the air.

        • by AmiMoJo (196126) *

          Satellite positioning doesn't work that way. The absolute error might be 10m, but it will be fairly consistent over tens of square kilometers and several hours. For reducing overlap it's fine.

    • by Flytrap (939609)

      ...Having everything rely on GPS, and thus on the budget the US chooses to spend keeping it working, is not a good idea.

      Everything does not rely on GPS... the iPhone, for example has had support for GPS as well GLONASS since the iPhone 4S (http://www.apple.com/iphone/specs.html). The iPhone seamlessly switches between the two satellite constellations (as well as Wi-Fi and GSM triangulation) so the consumer never really knows which system is being used to provide location services). So clearly the world is not solely dependent on the budget the US chooses to spend to keep GPS working; it is dependent upon the combined budgets

    • by evilviper (135110)

      Having everything rely on GPS, and thus on the budget the US chooses to spend keeping it working, is not a good idea.

      Right... Because the US almost exclusively using GPS-guided munitions, being in the process of converting the entirety of civil aviation over to GPS, and more, is a clear indication they're going to just let those GPS satellites fall out of the sky ANY TIME NOW.

      If other countries want to waste their money, be my guest, but let's be honest here... Other countries are putting up their own GPS

  • So now there's GPS, GLONASS, and Galileo. Is there going to be cooperation between the different sets of satellites, or will a given device only talk to its own set of satellites? It sucks, for example, when I'm hiking and can't get a GPS fix because I'm in a canyon with a view of only part of the sky. Ditto when all the visible satellites are near the horizon, so the vertical position's accuracy goes to hell, like a couple of weeks ago when I was at 7000' and it told me I was at 14000'. If we had a large n

  • by frovingslosh (582462) on Saturday October 13, 2012 @10:27PM (#41646601)

    because a minimum of four satellites are required in the sky for a smartphone or vehicle to use their signals to calculate a positional fix.

    Lets be more accurate here. A minimum of 4 satellites are required to be in the sky that can be observed at the same time from the same point on earth. Hopefully these satellites are relatively close together, because otherwise they might never all be visible at the same time. And if they are, since they are in low earth orbit they will pass by relatively quickly and only be briefly useable during each orbit. So, if the orbits are close this may allow a little bit of testing, but the "system" is still too satellite poor to be of any real use for navigation (at least unless you combine the signals with info from other U.S. or Russian satellites).

    • by hawguy (1600213)

      because a minimum of four satellites are required in the sky for a smartphone or vehicle to use their signals to calculate a positional fix.

      Lets be more accurate here. A minimum of 4 satellites are required to be in the sky that can be observed at the same time from the same point on earth. Hopefully these satellites are relatively close together, because otherwise they might never all be visible at the same time. And if they are, since they are in low earth orbit they will pass by relatively quickly and only be briefly useable during each orbit. So, if the orbits are close this may allow a little bit of testing, but the "system" is still too satellite poor to be of any real use for navigation (at least unless you combine the signals with info from other U.S. or Russian satellites).

      If you'd quoted the previous sentence: it becomes possible to test Galileo end-to-end, it'd be clear that they meant that it is possible to test the system, no one said it's a usable navigation system.

  • I wonder, since you can pretty much figure out what city you are in through ordinary radio and wifi beacons, not to mention the help you could get from having a clock and a sun locator, couldn't you really use GPS on the road with just two or three satellites?

    • All the equipment you listed is either more expensive, less precise, or not global; and triangulation in 3d space does not really work that way. Using just 2 satellites, you would get a circular area of possible positions, of which 2 would intercept the surface of the Earth and most likely the other would be far from Europe, but you lose altitude measurement and consumer products using the technology will not be reliable outside of Europe. An argument can be made that 3 is sufficient and most GPS devices wo

      • by bertok (226922)

        You also need to solve for time. Quartz oscillators aren't precise enough for a fix to within even kilometers, let alone meters.

        • You also need to solve for time. Quartz oscillators aren't precise enough for a fix to within even kilometers, let alone meters.

          I hadn't considered that we could use the 4th signal this way... that's really quite brilliant.

  • Apparently, there are units available that will track 120 simultaneous channels across all the available systems (this comes from Dave Wells). Not having a unit in my possession (and never having messed with Rinex before), I'll have to take his word for it.

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