Physical Distance vs. Signal Distance: An Analysis towards Better Location Fingerprinting

The laborious collection of location fingerprints, that could also potentially change with time, remains a hurdle towards the widespread deployment of indoor and campus area positioning using WiFi. In this paper, we present a preliminary analysis of the complicated relationship between distance in signal space, the physical distance and location errors towards better guidelines for fingerprint collection. We introduce the idea of entropy of location fingerprints and investigate the relationships between physical and signal distances, entropy, and expected errors with positioning using location fingerprinting. We present results with no access point and one access point and consider variations in the density of reference points and the standard deviation of signal strength to illustrate the issues.