Indoor Location Fingerprinting Using FM Radio Signals

Indoor positioning has become highly important because of the difficulties global positioning system experiences operating in such areas. Many wireless local area network indoor localization studies use the fingerprinting technique. In this study, a new positioning system is proposed based on frequency modulation (FM) broadcast as a signal of opportunity, with significant benefits for indoor positioning. This localization system uses FM signal strength fingerprinting. The deterministic and probabilistic approaches of fingerprinting are considered. A new method which is the combination of deterministic and probabilistic techniques is also proposed to improve the accuracy. Several algorithms are compared from four perspectives: mean distance error (MDE), data acquisition time, sensed channel number, and number of reference points. The results demonstrate that the combined method is the best, with a minimum MDE of less than 2.5 m. The comparison between using fingerprinting for FM and Wi-Fi is also discussed.