ABB AB91-1 HESG437479R1 HESG437899 module

Description

Traditional signal propagation is easily affected by refraction, reflection, diffraction, etc. The signal strength received by AB91-1 HESG437479R1 HESG437899 is the superposition of signals propagated through various channels. So sometimes the signal strength increases, and sometimes it decreases. After extensive practice, it has been found that the received signal strength follows a log normal distribution. Estimate the distance between nodes by the attenuation of signals during propagation, and solve the signal field strength received at a undetermined location based on the channel model:

In the formula: n is the path loss index, which is related to the surrounding environment; X σ is a normal random variable with a standard deviation of σ; D0 is the reference distance, usually taken as 1 m in indoor environments; PL (d0) is the signal strength of the reference position.

Assuming there are n APs and m reference labels, AB91-1 HESG437479R1 HESG437899, the strength of the undetermined label received by the AP point P=(AP1, AP2,…, APn), and the strength vector of the t-th reference label collected is St=(St1, St2,…, Stn), then the Euclidean distance between the undetermined label and the reference label St is:

The representative algorithm based on signal strength is the LANDMARC algorithm. This algorithm mainly compares different Et to find the reference label closest to the position of the undetermined label. When a test label is determined by K neighboring reference labels, we call it the “K-nearest neighbor algorithm”, and the coordinates of the test label are (x, y):