Vehicle positioning in underground space using a smart phone

Smartphones is a good choice for vehicle navigation since many navigation sensors are built-in with low cost advantage. However, it cannot provide reliable positioning information in underground space since GNSS is not available and IMU drift quickly. In this manuscript, a mixed navigation scheme for smartphone consumer is presented. It combines GNSS, INS, Non-Holonomic Constraint (NHC) and Bluetooth Low Energy (BLE) to provide reliable seamless navigation in both outdoors and underground. Some important problems including smartphone boresight misalignment, HNC level arm, GNSS and BLE time lag are discussed in the manuscript. The testing results show 3.1% /D horizontal positioning error in tunnel in INS/NHC positioning mode, and approximately 1 meter accuracy in underground parking garage in INS/NHC/BLE mode.