P³-LINS: Tightly Coupled PPP-GNSS/INS/LiDAR Navigation System With Effective Initialization

P3-LINS, a navigation system tightly coupling precise point positioning (PPP)-global navigation satellite system (GNSS)/inertial navigation system (INS)/light detection and ranging (LiDAR) with the DRANSAC-receiver autonomous integrity monitoring (RAIM) and the doppler iterative closet point algorithm (DICP) as its initialization procedure is established for accurate and reliable positioning in urban environments. The position initialization of P3-LINS is completed by the static PPP with the DRANSAC-RAIM algorithm. The yaw is initialized through the proposed DICP algorithm which relies on the quadratic constraint least-squares problem built by Doppler speed, LiDAR-simultaneous localization and mapping (SLAM) poses, and GNSS positions. After dealing with the initialization issue, the fusion framework of P3-LINS is constructed to handle the heterogeneous sensor data spatial–temporal consistency problem with the three-phase extended Kalman Filter (EKF)-based estimator. The experiments show that the initialization of P3-LINS achieves decimeter-level positioning error in minutes when keeping static and tenths of a degree-level yaw error after the vehicle moves a few seconds on the UrbanLoco. Moreover, P3-LINS outperforms the compared state-of-the-art methods in terms of positioning accuracy and reliability on both the public datasets and self-collected datasets.