
Ask HN: Think GPS like system but local - iamdumbman
Hey, actually i need to measure distance several points which will have barriers between them like human body and cloths etc...<p>I was thinking about infrared sensor but they can&#x27;t pass through the body.<p>GPS does work to find distance between two points.<p>But can i setup a local gps in a room so it gives me accuracy in millimetres instead of meters like with ordinary GPS? If so, how? Can you suggest anything better?<p>Distance between two points is limited to 8 feet max.
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ablerman
Differential GPS will get you 10cm accuracy. Getting into the mm range is a
whole other thing.

[https://en.wikipedia.org/wiki/Differential_GPS](https://en.wikipedia.org/wiki/Differential_GPS)

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choot
Wow, there aren't sensors which already are capable of measuring distance
between two points with error less than 1mm. (With barriers in between)

I am kinda shocked at the state of affair.

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thepapanoob
it really shows that you didnt even think about it once :D

look at how gps works (its really simple) then look at some passive systems
and some active ones

you will see why noone made an elegant solution yet

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iamdumbman
Can't believe there isn't already a system which is capable of offering error
within 1 millimetre.

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coldtea
Can't believe?

Because triangulation with signals from orbit passing through the atmosphere
is trivial?

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iamdumbman
I am not taking about GPS.

I need GPS like system with satellite confined in a room capable of resolution
within 1mm error.

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choot
I think there are several systems like LIDAR with less a millisecond error.

