I am currently working on this project where I have to find the location of a Wi-Fi enabled device such as our smartphone based. I can configure a raspberry pi to sniff out the wireless packet and measure the received packets based on the dBm. How can I find the exact location of the device? I don't understand how to do triangulation.
For tracking and triangulate some devices you need to measure the signal from differents points. You need to locate on the space some devices, that is the reason why you can't get a result with one signal strength, first, you need to put on a fixed locations some references to take the signal power. One you get that measure, you need to put that data on sone algorithm that calculate the distance taking on mind the losses on a typical propagation media, first you need to elaborate some ecuation with thats variables.
With a purely geometric approach (without calbration) and only signal strength as sensor, you require at least two and optimally four sensors.
Geometrically, a single signal strength sensor tells you the distance, all potential points lying equidistant on a sphere. You can probably rule out many possibilities but probably several solutions remain.
With a second sensor you get another sphere and when you intersect these two spheres the solution is a circle. While you can probably rule out most points, chances are that there are still possible points.
With a third sensor and yet another sphere which you intersect with the circle from before you get two points remaining. If you can't rule out either you need a fourth sensor, with its sphere only intersecting one of the points.
This is an idealistic, purely mathematic approach. Depending on local conditions, a real-world approach can be simpler or more complicated.
Triangulation is actually the opposite: you don't know the range but you know the direction. Each sensor tells you a direction or vector, two of which you intersect to get a single point in space.