A new smartphone-based indoor GPS positioning system

Abstract

The widespread use of GPS module in mobile devices causes the GPS-based positioning solution low cost, easy to use and access for end users. However, it is difficult for GNSS to provide reliable positioning information due to additional signal attenuation and blocking caused by buildings and construction materials. To take advantage of the embedded GPS module of mobile device in indoor environments without firmware/hardware-level modification, we propose a new GPS-based indoor positioning system. The main idea of the system is that the system separately forwards the outdoor GNSS signals to indoor environment through distributed indoor transmitting antennas. The crucial part of the system is Receiver-and-Transmitter (RX/Tx), which is able to separate and forward the outdoor signals to indoor environment. The theory and implementation of the Rx/Tx is introduced in the paper. The simulation results show the indoor positioning system is robust to the outdoor environments, such as ionospheric delay, tropospheric delay and so on. It is able to provide horizontal position with accuracy of about 2 m with the advantage of no hardware/firmware-level modification requirement on the mobile devices. The primary experimental test results show the feasibility of the proposed system but indoor multipath must be mitigated.