IMU-Aided Precise Point Positioning Performance Assessment with Smartphones in GNSS-Degraded Urban Environments

The tracking of satellite signals with the passive linearly polarized embedded global navigation system (GNSS) antenna smartphones in dynamic scenarios is susceptible to changing multipath and obstructions urban environments, which lead a significant decrease availability reliability GNSS solutions. Accordingly, based on characteristics smartphone inertial measurement unit (IMU) sensors data GNSS-degraded we established an IMU-aided uncombined precise point positioning (PPP) mathematical model that suitable for smartphones. To enhance initial alignment mode, step function variances depending carrier-to-noise density ratio were measurements, (INS) parameters initialized while both velocity position dilution precision (PDOP) reached corresponding thresholds. Considering noise observations gaps smartphones, robust Kalman filter (RKF) equivalent variance matrix was used parameter estimation improve convergence efficiency coupled PPP/INS model. Experimental results indicated proposed method can effectively performance environments. Compared conventional PPP scheme, horizontal errors eastern western areas long trajectory experiment decreased by 49.37% 48.29%, respectively. Meanwhile, deviation remain stable tunnel where are blocked.