On the accuracy of signal strength-based estimation techniques

In this paper, we address the problem of finding the inherent uncertainty of signal strength-based location estimation techniques. We propose a mathematical model for mapping uncertainty in signal strength space to uncertainty in physical space. We then analyze this model to compute the minimum value of the uncertainty in location estimation using signal strength measurements. The results of this analysis are used to draw conclusions about the dependence of the minimum uncertainty of various factors such as the signal variance, number of APs, distance between the APs and the propagation constant. We provide an argument linking the minimum uncertainty with a lower limit on the median error in location estimation using classification techniques.