I am currently reading a paper called "Indoor Localization for Bluetooth Low Energy Devices Using Weighted Off-set Triangulation Algorithm".
Now they use 3 reference points (APs) to triangulate the position of a person. If they find more than 3 reference points, they select the three best reference points.
To select the three best reference points they first look at the RSSI (received signal strength). Secondly they somehow calculate $W_r$ which indicates the quality of the triangle the three reference points defines.
$W_r$ is controlled by: - the shape of the triangle - the value of the distance ratio (which I think is the length of each side to each other, like L1/L2, L2/L3, L3/L1)
Now I find now way to calculate $W_r$ and wanted to ask if there is like a equation do this?