A Systematic Approach to Generate 3D Path Loss Heat Maps for WIFI Indoor Positioning ^†

To estimate the location of an object in an indoor environment, many indoor positioning techniques have been developed in recent decades. The popularity of indoor positioning systems has increased nowadays to enable the implementation of indoor location-based services. WIFI-based fingerprinting is one the most promising techniques to estimate the user or robot’s location in an indoor environment. Fingerprinting-based indoor positioning systems require the laborious task of environmental surveys to generate the fingerprinting database. This calibration process of a fingerprinting database causes the adaptability problem due to the high cost of the survey of the WIFI environment. Researchers have proposed different techniques to minimize the survey cost by means of the automatic generation of a fingerprinting database and its calibration. Most of these techniques only generate 2D path loss heat maps, while ignoring the height information of transmitting and receiving devices. In this paper, a systematic approach is presented to generate 3D path loss heat maps in which height information is also incorporated in the generation of more realistic 3D heat maps. The results show that the proposed technique for 3D environment generation outperformed the existing techniques, and the root mean square error (RMSE) is 2.17. Moreover, the proposed technique generated 3D heat maps effortlessly and its accuracy is almost equivalent to the real maps.