MOBILE TRIANGULATION OF WI-FI DEVICE



Mobile Triangulation of Wi-Fi Device



Mobile Triangulation of Wi-Fi Device based

The idea is to convert every geographical coordinate into a simple x,y,z coordinate (The Cartesian Coordinate system). After converting all geographical coordinates into Cartesian coordinates, we calculate the total weight of all the coordinates. After this - we simply add them all together (multiplying the respective coordinate with its weight), and divide by the total weight. We are then left with one coordinate, a single 3D Cartesian coordinate, that we can convert back to a Geographical coordinate using the trigonometric function atan2 and Pythagoras. The method is described on the next page. After that, I will code my own implementation, that can take a series of weighted coordinates and return a single coordinate. Then I'll test it, comparing with GeoMidPoints service.

Anyhow. Here's the method:

For every geographical point with the values, lon, lat and wht:

Convert to X,Y,Z:

Set the weight:

Note: If no weight is supplied, it's common to set it to 1. So:

Calculate the combined weight:

Calculate the weighted average coordinate:

Convert the weighted coordinate back to a geographic coordinate:

And there you have it. A weighted geographical midpoint.

Triangulation uses multiple access points to find a device based on the received signal strength of the device at each access point. Using algorithms, the location tracking system determines the intersection point of the device's signal at each access point to identify the device's most likely location. Triangulation is more accurate than the closest access point method, but not as precise as RF fingerprinting.

Using triangulation in a WLAN, an IT administrator initiates a command to find a wireless device and a call goes out to all access points on the network. Each access point that "hears" the device's signal responds to the request with information regarding signal strength. Access points that fail to hear the device do not respond.

The IT administrator waits an interval to ensure that each access point has had the opportunity to hear the device and that all access points have had a chance to report back. The more access points that respond, the greater the accuracy of the final result with the device's approximate location.

The location tool then draws coverage circles on a map around each access point that hears the device. Each coverage circle defines the boundary of the signal strength of the access point receiving the signal from the device. If an access point hears the device at -65 ...