Geomagnetism-Based Indoor Navigation by Offloading Strategy in NB-IoT

Abstract

Most indoor navigation technologies need to provide structure maps of buildings, but it is difficult to obtain these structure maps in practice. Therefore, we design a geomagnetism-based indoor navigation system without structure map of buildings by applying offloading strategy in narrow band Internet of Things. Why the geomagnetic signal can be used to achieve indoor navigation is due to its stability. We divide the indoor navigation into two parts: 1) the construction of signal fingerprint database and 2) the user navigation. First, the navigator carries out the signal acquisition of navigation route, and transfers the original signals to cloud server so as to construct the fingerprint database. Second, users can choose online navigation or offline navigation according to the actual situation. When choosing offline navigation, the users will employ dynamic time warping algorithm for fingerprint matching. When users would like to obtain better navigation results, they can choose online navigation. In this case, navigation system will offload the users’ sampling data to remote cloud, and then the cloud matches the fingerprint of geomagnetic signals by using particle filter algorithm and sends the computation results to the users so as to indicate the users’ moving direction. Experiment results demonstrate that our method is effective and the turning error is only 5 cm.