dRTI: Directional Radio Tomographic Imaging

TL;DR

This paper introduces dRTI, a directional radio tomographic imaging system that uses electronically switched directional antennas to enhance indoor localization accuracy by mitigating multipath effects.

Contribution

The paper presents a novel dRTI system employing directional antennas, along with methods for selecting optimal antenna directions to improve localization accuracy and reduce overhead.

Findings

dRTI significantly outperforms omni-directional RTI in diverse indoor environments.

Directional antennas improve radio link observations and localization accuracy.

Effective antenna direction selection reduces overhead while maintaining high accuracy.

Abstract

Radio tomographic imaging (RTI) enables device free localisation of people and objects in many challenging environments and situations. Its basic principle is to detect the changes in the statistics of some radio quality measurements in order to infer the presence of people and objects in the radio path. However, the localisation accuracy of RTI suffers from complicated radio propagation behaviours such as multipath fading and shadowing. In order to improve RTI localisation accuracy, we propose to use inexpensive and energy efficient electronically switched directional (ESD) antennas to improve the quality of radio link behaviour observations, and therefore, the localisation accuracy of RTI. We implement a directional RTI (dRTI) system to understand how directional antennas can be used to improve RTI localisation accuracy. We also study the impact of the choice of antenna directions on the localisation accuracy of dRTI and propose methods to effectively choose informative antenna directions to improve localisation accuracy while reducing overhead. We evaluate the performance of dRTI in diverse indoor environments and show that dRTI significantly outperforms the existing RTI localisation methods based on omni-directional antennas.