Smartphone indoor positioning system based on geomagnetic field

Due to the geomagnetic abnormality in indoor environment, made by various ferrous structural materials such as pipelines, the magnetic signals of a region are regularly different and sustainable. In this paper, we develop an application based on the Android system to implement the indoor geomagnetic positioning. To estimate the pedestrian's position, the real-time geomagnetic sequence measured by smartphone's sensors is compared to the measurement with the offline database that has been created for an experimental field in advance. To satisfy the use in real life, the attitude conversion, one of the relative algorithms and techniques, is applied to solve oriented problems introduced by the heading offset. In addition, LSM (Least Squares Method) and improved MSD (Mean Square Difference) for matching similarity measurement have been built with high precision. The application has been repeatedly tested on various real-case scenarios, whose accuracy could be controlled within 1.2 meters.