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0 pointsuntog12y ago0 comments

Did you ever manage to get it to be accurate, though? I tried something similar but the accelerometer and gyro were nowhere near accurate enough.

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7 comments · 4 top-level

digikata12y ago· 3 in thread

It's unlikely to be standard inertial navigation, mems sensors drift with dead reckoning integration pretty quickly, even applying more sophisticated kalman filtering may not improve things indoors without GPS (or sufficient travel for GPS even if you could receive it consistently)... But, if you were to add "room-like" assumptions it might improve things pretty well, eg. when integrating a rotation, fit it to a 90 degree corner, similar with traversal, fit it to travel along a wall. With those basic assumptions, I'm guessing you can correct a lot of the raw integration drift. If this is true, my guess is it would start break down in unconventional rooms - octagonal rooms, non parallel walls, etc...

wizzard12y ago

Bingo. Here's an example from a room with a centered bay window: http://images.younghouselove.com.s3.amazonaws.com/2014/02/Ap... So you have to go back with a measuring tape and amend all the measurements anyway, because it's so inaccurate.

Full article reviewing MagicPlan and RoomScan: http://www.younghouselove.com/2014/03/apps-and-zerts/

marcosscriven12y ago

I wondered about doing something like this a while back - and it was the very quick cumulative error from double integration of acceleration data that stopped me from even trying. Clever idea getting the user to place the phone on the walls - as you say that would correct a lot of the errors. But also, as you say, unconventional room layouts get you back to square one so to speak.

digikata12y ago

I haven't played around with the latest generation of sensors, but if the time/distance error growth is small enough, maybe you can get model corrections down to the nearest 45 deg. If you can hit that threshold, you might end up fairly functional with possibly the next largest segment of non-rectangular rooms.

CamperBob212y ago

Supposedly, there's a rule of thumb that says that dead reckoning by integrating readings with a MEMS sensor is about as good as walking around with your eyes closed. I didn't even get mine working that well when I tried, but I'm sure it's possible if you get the pre-integration noise filtering right.

Lately I've seen a lot of app notes and open-source code written by/for amateur drone guidance developers, which I suspect would have helped me a lot.

dclowd990112y ago

Not even close. I was approaching the filtering mechanisms before I started a new job and started focusing my efforts on that.

LukaszB12y ago

Try this http://www.cs.huji.ac.il/~gaddi/3D%20Motion%20tracking%20wit...

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