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by KeplerBoy 902 days ago
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.

2 comments

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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)