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...

I was thinking about infrared sensor but they can't pass through the body.

GPS does work to find distance between two points.

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?

Distance between two points is limited to 8 feet max.

[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

[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.

[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

[iamdumbman → thepapanoob]

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

[coldtea → iamdumbman]

Can't believe?

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

[iamdumbman → coldtea]

I am not taking about GPS.

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

[choot → iamdumbman]

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