Selective AP-sequence Based Indoor Localization without Site Survey

TL;DR

This paper introduces an indoor localization method using ordered AP sequences that eliminates the need for site surveys, enabling quick fingerprint map creation and achieving sub-5 meter accuracy.

Contribution

It presents a novel AP-sequence based localization system that does not require laborious site surveys, simplifying deployment and maintaining competitive accuracy.

Findings

Achieves < 5m localization accuracy in experiments.

Using fewer APs can outperform using all APs for localization.

Fingerprint map creation takes less than a second offline.

Abstract

In this paper, we propose an indoor localization system employing ordered sequence of access points (APs) based on received signal strength (RSS). Unlike existing indoor localization systems, our approach does not require any time-consuming and laborious site survey phase to characterize the radio signals in the environment. To be precise, we construct the fingerprint map by cutting the layouts of the interested area into regions with only the knowledge of positions of APs. This can be done offline within a second and has a potential for practical use. The localization is then achieved by matching the ordered AP-sequence to the ones in the fingerprint map. Different from traditional fingerprinting that employing all APs information, we use only selected APs to perform localization, due to the fact that, without site survey, the possibility in obtaining the correct AP sequence is lower if it involves more APs. Experimental results show that, the proposed system achieves localization accuracy < 5m with an accumulative density function (CDF) of 50% to 60% depending on the density of APs. Furthermore, we observe that, using all APs for localization might not achieve the best localization accuracy, e.g. in our case, 4 APs out of total 7 APs achieves the best performance. In practice, the number of APs used to perform localization should be a design parameter based on the placement of APs.