Radio Triangulation (GPS minus space)

Okay, my idea is that in the event of the zombie apocalypse (or many others) I think it would be very handy to have a GPS-esque service.  I've read that the satellites we use for GPS are decaying and will not be around for much longer than 20 or 30 years without repair or replacement.  So, in the event that the zombies come and I manage to survive and, more importantly, thrive, I would like to be able to set something along these lines up.

Assuming I have access to renewable power sources and the correct materials, how would I build something like this?  My initial thought is to use radio towers for triangulation.  I go to three existing radio towers, set them up with a power source, and set them to frequencies A, B and C respectively.  Then i have a (preferably mobile) device that monitors the signal strength of those towers.  Another option that springs to mind is that i might have multiple antennae that i can connect to a few feet of wire each and place around my device for added accuracy. If my idea is sound, I then will have a way to tell where i am, roughly.

Of course, not only will I need a method of recording locations in a logic manner, I also have to worry about the accuracy of my readings, due to the limitations of my device/radio towers, possible weather conditions or even my physical location (valleys, cliffs, etc).

I should add that I'm looking for a very simple reproducible device here, not a standard GPS with loaded maps or the like.  I'm fine with having a receiver and a notebook for locations, or just marking them down on a physical map.  I don't know much about radios or GPS, I'm afraid, and would greatly appreciate any advice.  Thanks!

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NachoMahma6 years ago
.  It should be doable. As you seem to be aware of, accuracy may suffer at times because of reflections/obstructions, but it should meet your requirements..
.  Instead of using only relative signal strength, I'd try using highly directional antennae to determine direction to transmitters for triangulation.
.  As Arano points out, you can use just two antennae and throw away the obviously wrong answer, but, IIRC, you will lose some resolution.
.  BTW, you won't be able to compute altitude.
its not like i think its a bad idea, buti kinda dont like the directional antenna idea... if you do the same with eyes and some 'special' points(like the signals for the antenna) in the environment you get the same or better accuracy, because you won't have any disturbing interference or reflections... in addition if you dont have a rough idea where the radiotowers are you may have a hard time when you search the signal
Someone's already done it here.
vindicien6 years ago
Hi guys !

I'm currently working on a project that will help blind people to move in my school. The main aim is to give a remote control to him, and when he push a button, the remote tells him where he is.

For that, I would like to create a kind of triangulation inside the building.
And when creating a map of the school with the coordonates of each room and antenna, I can know exactly where he is.
The problem is that there are many walls... And so I don't know wich technologies to use !

Using ultrasounds ? radio ? Zigbee ?
Any idea that would help me ?

theMij (author) 6 years ago
Did this work? It's my first time posting on the forums and I can't see my topic anywhere but the 'You' link up top, and when not signed in it's nowhere in sight.
Arano theMij6 years ago
yes you made succesfully a topic... to your idea: if i remember right something like this was used by the airforce or luftwaffe during WW2 though they were flying and thus had no problems like cliffs... and if you have a very rough idea where you are you need only 2 towers, because one of the 2 possible points where you are is wrong and you can determine which one.