Precision of RSS-Based Localization in the IoT

Abstract

Currently, the most popular indoor geolocation technique used in smart device is the RSS-based Wi-Fi localization. The general accuracy of Wi-Fi localization in around 10–15 m. To improve this accuracy in indoor areas, site survey is commonly used to collect a signature data base. With the emergence of smart buildings and the IoT to connect the sensors for the smart building, a number of low power sensor devices with diversified power levels will be deployed in the building. The radiated RSS from these devices can be used to improve the precision of the RSS based localization. In this paper we introduce an analytical frame work for calculation of the CRLB in an environment with variable radiated powers from sensors to complement the Wi-Fi localization. We use the analytical framework to demonstrate the accuracy of localization in the third floor of the Atwater Kent Laboratory at Worcester Polytechnic Institue, for existin Wi-Fi localization and variety of sensor deployment scenarios. The existing CRLB calculation for the RSS-Based localization use the differential value of the received signal strength from given reference points to calculate the variance of the location estimate. As a result, effect of the transmitted power from the sources is eliminated. In another words this approach cannot demonstrate the effects of transmitted power of the reference device on the performance of the system. By introducing the concept of certainty in the measurement of the RSS, we also introduce a novel model for calculation of the performance of RSS based localization with inclusion of the effects of the transmitted power from the reference sources.