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World's first GPS-free quantum navigation trial succeeds at sea (interestingengineering.com)
submitted 5 days ago by to c/technology@lemmy.world
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[–] 14 points 4 days ago (4 children)

Two issues I have with the presentation:

A magnetic field is an external signal - the Earth's magnetic field is actually incredibly weak...

10x better performance than GNSS ... positioning accuracy of 1 nautical mile. Cheap old school handheld GPS out in the woods was accurate better than 10 feet most of the time, so what in this performance is 10x better? 10x more resistant to jamming? Seems like it should be completely impervious to jamming. 1 nm accuracy is useful, but hardly better performance.

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  • [–] 16 points 4 days ago (1 child)

    Its better performance than existing non-gps systems - not better than GPS. For ships , being within 1nm after thousands of miles of travel is really well performing. Obvious the real play here is weaponry though, since GPS isnt reliable in warfare and on-board sensors can do the detail work of target identification once in an area, the hard part is a way for them to self navigate accurately over long distances without GPS.

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  • [–] 13 points 4 days ago (2 children)

    The realer play is submarines. You don't get any satellite signal at all underwater. Before this it was only INS or dead reckoning.

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  • [–] 3 points 4 days ago (2 children)

    I suspect submarines can also use bottom facing radar to track features on the sea floor. But tracking the gravity should be even better.

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  • [–] 8 points 4 days ago (1 child)

    Radar is radio, just like most satellites. It doesn't do well through water. And that would require emissions, which submarines like to avoid.

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  • [–] 6 points 4 days ago

    I'm guessing they meant sonar instead. AFAIK active sonar does work really well, but is rarely used since it reveals your location twice as far as you're able to detect others. Not to mention the horrible effects on wildlife - the sound waves carry so much energy that a point-blank hit is somewhere between "lethal & untreatable" and "turned into red mist".

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  • [–] 6 points 4 days ago (1 child)

    GPS is vulnerable to various attacks.

    It's unclear what the capabilities are, but there IS a Russian satellite that HAS jammed GPS for almost a whole hemisphere. It's operated several times for a couple seconds over these past few years.

    Veritassium did a great presentation on how we know this.

    https://youtu.be/tz23G_UXCGA

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