Indoor Navigation by WLAN Location Fingerprinting - Reducing Training-Efforts with Interpolated Radio Map

Abstract —Due to the fact that smartphones are today alreadyused by about one out of seven persons worldwide and theircapabilities concerning hardware and sensors are growing,many different indoor navigation solutions for smartphonesexist. The solution presented in this paper is based on WirelessLocal Area Network Location Fingerprinting. Fingerprintingis a method where signals at a number of specific points aremeasured once and stored in a database that is needed todetermine the position later on. Measuring each and everyfingerprint makes the off-line phase a complex and very time-intensive process, especially for big buildings. The bigger thebuilding, the higher is the effort to create the map needed forthe on-line phase to determine the position of a device. In orderto cope with this complexity, an approach for optimizing theoff-line phase is realized. The system substantially lowers thenumber of positions at which fingerprint measurements haveto be taken by identifying ideal positions. All other non-measured fingerprints are determined by using a form of theLog-Distance Path Loss Model.