Integrity monitoring of multi-constellation GNSS-based precise velocity determination in urban environments

Precise velocity determination is an important topic for automatic applications. However, multiple abnormal global navigation satellite system (GNSS) based velocities inevitably exist with degraded performance even after traditional quality control of GNSS observations in urban environments. To improve the reliability of velocity, hybrid velocity based on solution separation (SS) is proposed to monitor time-differenced carrier phase (TDCP), Doppler, and code-based velocity solutions. A public low-cost GNSS dataset of kinematic vehicle tests in Tokyo's urban canyons is applied to verify the proposed method. Results show that the SS test of the proposed method can effectively improve velocity accuracy by removing faulty velocity estimations. Besides, it is able to provide a 99.66% availability of velocity estimation. The hybrid IM-based velocity method achieves an improved perfor-mance both considering availability and accuracy, which could provide precise velocity with high availability and reliability for support of GNSS-based and multi-sensor-based positioning for autonomous navigation in signal-denying environments.