Figure 4.

Example of application of the weighted k-nearest neighbor (WKNN) algorithm for two reference points, RP₁ and RP₂, one test point, TP, and three beacons, B₁, B₂ and B₃: (a) Calculation of the estimated coordinates $\left(x_e,y_e\right)$ as a weighted average of the coordinates of k-nearest RPs (k = 2) with the shortest distance to the TP in the signal space; (b) Euclidean distances of the RPs to the TP in the signal space.