Due to the ease of development and inexpensiveness, indoor localization systems are getting a significant attention but, with recent advancement in context and location aware technologies, the solutions for indoor tracking and localization had become more critical. Ranging methods play a basic role in the localization system, in which received signal strength indicator- (RSSI-) based ranging technique gets the most attraction. To predict the position of an unknown node, RSSI measurement is an easy and reliable method for distance estimation. In indoor environments, the accuracy of the RSSI-based localization method is affected by strong variation, specially often containing substantial amounts of metal and other such reflective materials that affect the propagation of radio-frequency signals in nontrivial ways, causing multipath effects, dead spots, noise, and interference. This paper proposes an adaptive smoother based location and tracking algorithm for indoor positioning by making fusion of RSSI and link quality indicator (LQI), which is particularly well suited to support context aware computing. The experimental results showed that the proposed mathematical method can reduce the average error around 25%, and it is always better than the other existing interference avoidance algorithms. 1. Introduction Due to the ease in deployment, inexpensiveness and potential applications in the smart building, security, and healthcare, indoor localization system gets significant attentions in these recent years. Mobile positioning has become increasingly interesting system most notably for context-aware application and emergency services, which works in ad hoc manner. Global positioning system (GPS) has been the mainstream technology for location and tracking for outdoor environment but the positioning within indoor environments does not permit a positioning with GPS (or only with poor quality). It generally requires a direct view to several satellites, resulting in limited performance for indoor environments. GPS signal in an indoor environment is too faint to provide sufficient accuracy. Development of non-GPS-based solutions is thus of great interest for indoor use based on existing signals and hardware, as well as new systems and sensor modalities. A number of commercial systems and research prototypes are developed with different kinds of localization methods. This method usually use infrared (IR) [1], ultrasound [2–4], or radio-frequency (RF) system [5–7]. Different sensors provide a different range of accuracy from centimeters to room level. It seems as
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