The vehicle-mounted RTK positioning unit is composed of an online NRTK service, high-precision vehicle RTK receiver, dual antennas, inertial measurement unit (IMU), and vehicle data processing module. The base station transmits real-time differential correction data through wireless links. The onboard unit fuses satellite positioning data, correction information and inertial attitude data to output continuous centimeter-level vehicle positioning results. It provides accurate vehicle latitude, longitude, heading and elevation information for autonomous driving perception, path planning and vehicle control, ensuring driving stability and safety in complex traffic scenarios.