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Comment by samstave | Hacker News Reader

>reminder that our super accurate GPS measurements are not 100% reliable

Lockheed solved this with their super sensitive Magnetic Field 'GPS' device - which they claim if for having 'GPS' accuracy for aircraft and ships nearly 100% based on the localized magnetic signature of the earth - but we all know these are actually built for subterranian/submarine environs where space based GPS no cut it. Can't navigate Agartha without it.

https://www.gpsworld.com/quantum-magnetometer-senses-its-pla...

I do wonder how much major earthquakes affect the finer signature of the magnetic fields?

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How is this solved?

The surface of the earth just shifted in a highly non-linear and non-uniform way. Places are not at the same coordinates or at the same distances from each other they were last week.

Read the link. The quantum magnetic locator doesnt use GPS satellites, so the "our GPS is not 100% accurate" is solved by the magnetic quantum thing... its just not available on _your_ smartphone.

Re-read my post, I believe that the real use of Lockheeds Quantum GPS is for subterranian and submarine navigation more than it is for aircraft - hoever, if we can map the magnetosphere of other planets, say, mars, then this could be a non-satellite-dependant GPS for any body in space where we know the magnetic signature based on probes... although said probes could also double as GPS satellites for the planet they are probing should we add such equipment, it would seem.

But the problem is not the accuracy, it's the temporal stability. GPS is accurate enough, but it's no good if the physical locations shift over time.

Most people need an up-to-date map, not just a location on a map.

Related - Farmers ‘crippled’ by satellite failure as GPS-guided tractors grind to a halt 181 points 8 months ago 150 comments https://news.ycombinator.com/item?id=35643705 -- https://www.smh.com.au/national/farmers-crippled-by-satellit...

GPS is only accurate up to 16 feet, and unless you are very close to an earthquake or other deformation source probably everything around you has moved by the same amount.

Most people only use GPS for local navigation.

GPS is much better than 16 feet these days.

Nobody asks google maps for instructions how to move 10 miles southwest. We ask it to provide a route to a specific latitude and longitude, that's global navigation and that, of course, doesn't work if the place you want to get to has gotten new coordinates overnight.

That 16 ft figure is provided by the government. https://www.gps.gov/systems/gps/performance/accuracy/

And of course, satellite navigation is worsened by the urban canyon of buildings, terrain, trees etc so super accurate navigation also uses local cell towers, which are also shifting by the same magnitude and direction as you and your local destination.

Ultimately people only really need to get to the rough city block of where they need to be, and so as long as buildings are not shifting hundreds of feet a year it is mostly not noticeable.

From that source:

> GPS-enabled smartphones are typically accurate to within a 4.9 m (16 ft.) radius

Smartphones were typically optimized for speed and battery life, not accuracy. Now that Multi-Band GPS is available on high end smartphones, they tend to be more accurate.

Also almost every smartphone I know of has acceleration sensors and can do Kalman filtering of the GPS position to achieve a much higher accuracy in practical use, even if the individual measurements are only accurate to ~5 meters.

They add fuzz to RSSI algos due to accelerometers trying to predict direction ofmotion for telemetry aiming.

swarm that on that backend with GPS tlemetry and typical rssi from cell towers, and the IMEI - and you have precise targets... with bios on the tracker (phone) - cams, gait, finger, face, voice, face... May as well start developing smart fabric... Oh wait...

:-)

Cyberpunk is dystopian by mr(crisper)DNA (TM)

Could even use this as a revers GLOBAL ORBITING SYSTEM [GoS] - Whereby a single satellite|probe dispels a lander to a planet with the Quantum Magnetic Cannister, and that QMC signals its global location to the satellite launcher, and the satellit can extrap its location based on the absolute location of the ground guys... (might need more than one ground magnet-moles?)

How can this be measured? Can fluidx3d do martian magnetics? [0]

[0] https://github.com/ProjectPhysX/FluidX3D

---

EDIT: "Mars does not have a magnetosphere"

ELI5: "how do electronics work when there is zero magnetic field around them? A complete antimagnetic environ?"

I've never heard any mention about making any electrical device work on a planet (such as mars) in a complete magnetically dark location?

How is there gravity on mars if there is no magnetic field for a planet, and how can mass, the size of a planet not produce magnetism/gravity if its not made of iron-sh (the RED of the planet)

ELI5, please.

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