Device-based Real-time Single User Indoor Localization Using Internet of
Things
Authors: Meena Bhagwan S. , Hemachandran Kattamanchi 
Published: July 2021

Background:
Localization is an important area of implementation of the internet of things based
on Wireless Sensor Networks. Outdoor user tracking is possible using the global positioning system;
however, the global positioning system accuracy decreases in indoor environments. To overcome this
problem, the wireless sensor network is used in internet of things-based technology for localization.

Objective:
The wireless sensor network-based indoor localization is categorized into two categories; rangebased
and range-free localization. In range-based localization, it first computes the relative distance and then
calculates relative coordinates. In range-based techniques, distance and position are calculated. The internet
of things-based localization uses the range-based and range-free techniques of a wireless sensor network to
localize any object. The Light Dependent Resistor-based localization work has been proposed in previous
research. In this research, the light-dependent resistor traces a person’s entry /exit event as the person
switches ON/OFF lights of the building. However, it was not a sufficient effort to localize a person using
light dependent resistor. To overcome the problem of light dependent resistor, the two PIR sensors have been
used in each room along with one RFID based approach in this study.

Methods:
An indoor scenario has been considered in this study. The hardware setup has been configured to
trace the user. When a user enters inside a building, he will switch on the lights, and the light sensor records
the light intensity and gives some reading. The difference in the reading of the light sensor (before switching
ON the light and after switching OFF the light) gives some clue about a user in an indoor scenario.
Nevertheless, if the lights of many rooms remain switched ON, then the user cannot be localized using the
above method. In order to sort out this ambiguity of light sensors, two passive infrared sensors in each room
along with one radio frequency identification-based model have been proposed in the present study.
Implementing the single-user localization using a light-dependent resistor sensor becomes erroneous if a
person moves from one room to another and the lights get turned ON/OFF. Moreover, the LDR-based model
is affected by sunlight during the daytime.

Results:
As the implementation of passive infrared sensors along with one RFID-based localization
technique gives 93% efficiency, the light-dependent resistor-based localization system gives an efficiency of
35%.

Conclusion:
The light-dependent resistor-based approach is prone to more errors because the user may enter
multiple rooms while the lights of each room remain ON. To overcome this problem, a passive infrared
sensor and radio frequency identification-based approach for a single user indoor localization has been
proposed. The proposed techniques are easy and cost-effective for implementation. The results show that the
proposed technique provides better localization accuracy than a light-dependent sensor-based technique for
single-user indoor localization.