The precise localization by using Wi-Fi Access Point (AP)
Keywords: Indoor radio propagation, locating algorithms, laptop as a receiver, signal analysis, WiFiCopyright © 2016 Universitas Ahmad Dahlan. All rights reserved.
IntroductionLocating is an essential technology which finds lots of industrial applications such as marketing, rehabilitation campuses, military and security applications, and so on [1][2][3][4][5]. Instead locating technologies and its applications are either time based or radio signal strength (RSSI) based systems, most of the technologies prefer RSSI based systems. GPS and cellular based systems have very satisfied location precision capability at outdoor, but they have almost no capability (GPS) or limited capability (cellular) to cover for indoor positioning. It should be noted that cellular technologies are also operator dependent, not flexible, and not applicable to indoor locating. In order to increase the performance of indoor positioning services, most indoor locating systems use multilateration on fingerprinting positioning methods [2]. Fixing a location requires some reference frames to describe positions relative to those pre-determined references, and frames are commonly called as coordinate systems in which any location is specified with respect to its origin. Indoor locating technologies are rapidly growing as a result of an increase in popularity of mobile equipment. This popularity requires that development of a proper propagation model and locating algorithms are essentials for uninterrupted and/or precise locating systems in an indoor environment. Requirement to use of a proper model forces scientists to investigate propagation mechanisms [1][2][3][4][5][6][7]. There is also tremendous increase in Wi-Fi localization system applications in an autonomously navigating robot project [3,4]. Such models, basically, use Wi-Fi signature map with geometric constraints and introduce a continuous perceptual model of the environment generated from the discrete graphbased Wi-Fi signal strength sampling. Continuous localization techniques referring to known reference points are slightly different than the certain location identification at any time.RSSI based in building positioning systems are growing very rapidly in two ways. One way of indoor positioning is passive-localization and the other one is called active-localization. Passive-localization systems are basically based on Radio Frequency Identification RFID technologies which do not allow two way communications, but provide comparably accurate location [5,6]. Ozdenizci, et al.,[6] present a case study for the system requirements giving the design details. They compared their proposed approach with existing indoor navigation