Heading enhancement algorithm of GNSS/IMU integrated navigation based on dual-antenna TDCP

In global navigation satellite system (GNSS) and inertial measurement units (IMU) integrated navigation systems, attitude estimation, especially the accurate heading estimation, is very important for the real-time monitoring of vehicle state. However, due to the divergence of IMU on the altitude channel, its errors will gradually accumulate if the IMU cannot be accurately constrained, so the estimation accuracy of the heading is insufficient in the vehicle application where the heading changes frequently. In order to solve the problem of poor attitude estimation accuracy in GNSS and IMU loosely coupled navigation, a heading enhancement algorithm of GNSS/IMU integrated navigation based on dual-antenna time-differenced carrier phase (TDCP) is proposed. The vehicle heading is solved by dual-antenna TDCP to increase the input dimension of observations in integrated navigation filtering, and the Hatch filter and robust adaptive filter are used to improve the pseudorange accuracy of the observation domain and the GNSS/IMU integrated navigation positioning and attitude estimation performance, respectively. The algorithm evaluation results based on the measured data show that compared with the traditional GNSS/IMU integrated navigation method, the proposed algorithm improves the positioning and velocity measurement accuracy by 22.12% and 41.27%, respectively, and the heading accuracy by 46.29%.