Indoor distance based positioning by using metrics of standard communication technologies

In recent years, indoor localization problem is a highly preferred topic to study. In this thesis, a positioning system based on wireless communication metrics is proposed and implemented for a 4 client robotic team in an indoor environment. It is aimed to estimate the distances between the clients by using the received signal strength measurements. By using the estimated distances, the relative positions of the clients are identified by the proposed no initial indoor positioning algorithm. In this thesis, besides the preferred wireless communication metric, Received Signal Strength Indicator (RSSI), the other metrics, Time Difference of Arrival (TDoA), Time of Arrival (ToA) and Two-Way ToA are also examined. With the selected hardware it is considered to use RSSI instead of time based metrics in order to implement a short range low cost indoor positioning system. The RSSI measurements are recorded more than once for two different indoor environments and four different client layouts. By using those recordings the distances between the clients are estimated. For 4 clients, 6 different distance values are estimated by using 3 different Received Signal Strength (RSS) based distance estimation methods namely International Telecommunication Union (ITU) Indoor Path Loss Model, Two-Ray Ground Reflected Path Loss Model and the Experimentally Derived Signal Strength Distance Relation (EDR) Model. The distance estimations for 4 clients, 3 distance estimation methods and two environments are recorded to be used in No Initial Indoor Positioning algorithm, the NOIP. The proposed positioning algorithm, the NOIP, is a triangulation based positioning algorithm that needs no initial conditions. The position estimations of the clients for all the client layouts are presented for the specific hardware and environment selection. The usability of the system is discussed and some additional information is provided to improve the quality, efficiency and availability of the system.