Assessment of Ultra-Tightly Coupled GNSS/INS Integration System towards Autonomous Ground Vehicle Navigation Using Smartphone IMU

An ultra-tightly coupled (UTC) GNSS/INS integration navigation system is established and researched for the autonomous ground vehicle navigation based on the consumer-level inertial measurement unit (IMU). The used IMU is chosen from a smartphone in this work. The proposed integration architecture is tested with a GNSS software-defined receiver (SDR) using the vector tracking (VT) technique. The UTC integration system which is measured through both GNSS measurements and the IMU data is an upgraded version of the vector tracking technique. Meanwhile, the performances of both the integration solutions and the GNSS solutions can be improved by such advanced technology. An extremely challenging environment is chosen to verify the navigation performance. The loosely coupled (LC) GNSS/INS integration navigation system using the vector GNSS SDR and a commercial U-Blox GNSS receiver are also tested in the same scenario as comparisons. The field test results demonstrate that the proposed ultra-tight coupling algorithm can enhance the availability of the navigation solutions.