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How would one track the position of a person in a building? I have an idea but I am unsure of its validity.

Provided wifi nodes are setup in known positions around a building, one could trilaterate the position of the person. Because the distance between the nodes is already known , things like a wifi signal passing through different objects can be compensated for. Every few seconds a test would run comparing what the signal strength should be from node to node. If the signal strength varies from what is expected then we can expect that the signal is passing through a different material. These tests would give a constant "weight" that would then be used in trilateralation.

I have also tried to find velocity sensors but with no such luck. Accelerometers work but what if the object you want to track is traveling at a constant speed? Wouldn't the accelerometers then read 0?

GPS does not provide anywhere near the accuracy I need.

This is all speculation and I don't know the math behind it as of yet.

The eventual application of this is to build a system that tracks firefighters or other rescue workers within a building. The building's blueprints would be stored on a computer and their positions would be mapped on the wireframe layout of the building. Allowing others on the outside to find them in the event of becoming trapped.

Buildings aflame, funnily enough, provide very little light. In some situations you can not see your hand in front of your face. Because of this, sensors that rely on optics probably would not work that well.

Originally I started using my android phone but found its sensors lacking. Any ideas for tracking persons inside a building would be welcome.

This has been marked as offtopic but I have found a useful library for anyone looking to do something similar.

http://kootenpv.github.io/2016-09-19-predict-where-you-are-indoors

Bruk Habtu
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    In a disaster situation inside a building you should not trust the building infrastructure to help you. – Dr. belisarius Jun 11 '11 at 04:08
  • This is a bit vague - you're really talking about a concept for an application rather than a programming or development problem. I vote off-topic for migration to programmers. – Kirk Broadhurst Jun 11 '11 at 04:13
  • Even without the blueprints, being able to get the position of a person on 3 axes would be helpful. If the building collapses you have an idea of where someone is. – Bruk Habtu Jun 11 '11 at 04:14
  • @Bruk if the people are going to have Wifi or GPS devices, why not just give them emergency beacons? Have the rescue team use electromagnetic detection tools. And what chance of building collapsing, anyway? – Kirk Broadhurst Jun 11 '11 at 04:17
  • @Kirk I saw the physics and math tags so I was hoping to get some algorithms or some ideas of how to weigh things like wifi signals vs accelerometers. But you are correct. This is a bit offtopic. It is a combination of hardware, physics and programming but at this stage it is a lot more hardware and physics than it is code. Is there a way to close a post? If not I will remove the above. – Bruk Habtu Jun 11 '11 at 04:18
  • @Bruk I mean: you should not trust that sensors inside the building will be functional when needed. Rescue teams usually carry their own sensors for trilateration or triangulation and the fireman has the _emitter_ (beacon) with him. – Dr. belisarius Jun 11 '11 at 04:20
  • @Kirk the only reason for wifi is that I was playing with my android phone for location and the accelerometers werent accurate enough. Started off working on the wifi trilateration code in python. I am exploring all ideas right now. A beacon would be a great idea. – Bruk Habtu Jun 11 '11 at 04:21
  • @Bruk Users with enough rep points can close posts. I'm sure someone will come along and do it soon enough. – Kirk Broadhurst Jun 11 '11 at 04:21
  • @belisarius: I understand what you mean now. As far as i know, firefighters here do not carry any existing emitters. I did not encounter them in any of my training. Do you happen to know which systems are already in place? – Bruk Habtu Jun 11 '11 at 04:22
  • @Bruk See for example http://www.summitsafetyinc.com/products/trackers/index.html – Dr. belisarius Jun 11 '11 at 04:25
  • @belisaurius: Thanks for the link! I'm sure there are whitepapers around describing how it works. – Bruk Habtu Jun 11 '11 at 04:26
  • @Bruk Good luck with your project! – Dr. belisarius Jun 11 '11 at 04:28

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