Objectives Recognizing that the global navigation satellite system (GNSS) signals are seriously occluded in urban environments, it is a great challenge to achieve continuous and reliable positioning services via smartphones.
Methods An improved smartphone GNSS/micro-electro-mechanical system inertial measurement unit (MEMS IMU) tightly-coupled integration method for vehicular navigation is proposed. Specifically, the smartphone navigation system firstly conduct time updates with inertial navigation system mechanization algorithm. Then the measurement updates are realized by GNSS pseudorange, Doppler and headingangle derived by time differenced carrier phase, besides virtual constraints of vehicle motion.
Results Vehicular navigation experiments using three different smartphones were carried out to evaluate the performance of the proposed algorithm. The results show that continues and reliable positioning solutions are achieved in urbanchallenging environments with horizontal and vertical accuracy of 5-6 m and 5 m in terms of root mean square, and short-term continuous navigation is also available even in tunnel scenarios where GNSS signals are totally blocked.
Conclusions The proposed algorithm is less affected by the GNSS observation environment, and can improve the continuity and reliability of smartphone vehicular positioning greatly in urban complex environments.
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