Issues and challenges in RSSI based target localization and tracking in wireless sensor networks

Moving target localization & tracking has been currently widely addressed area of research because of its lot of significance in broad varying applications. The major approaches for target localization & tracking in a defined WSN are Range Based, Range Free, Prediction Filter based Approaches aimed at achieving either Localization & Tracking accuracy or Energy Efficiency or Security or combination of these depending upon application at hand. Besides other range based techniques (TOA, TDOA, AOA) aimed at localization/tracking, RSSI-based approach is most widely used in spite of various challenges associated with it. The most important reason is that it does not need the extra hardware as most of electronic gadgets have built-in RSSI Circuitry to read RSS. By exploiting this RSSI measurement, one can find distance between transmitter & receiver using a suitable mathematical model of signal attenuation. However due to high dynamicity of wireless environment, the RSSI measurements are notoriously unpredictable. This paper discusses the RSSI based localization & tracking problem in detail & also surveys various other solutions proposed by the research community in the domain. Recent strategies to improve localization accuracy & tracking accuracy in RSSI based systems especially for dynamic environments & open research issues are also discussed as well.