A GNSS/IMU/Vision Ultra-Tightly Integrated Navigation System for Low Altitude Aircraft

In order to solve the problem of poor anti-interference ability of GNSS/IMU ultra-tight integrated navigation system under high dynamic and harsh environments, a visual assisted GNSS/IMU ultra-tight integrated navigation method is studied. The attitude and position information provided by binocular vision are introduced into the GNSS/IMU ultra-tight integrated navigation system. The state equation of the traditional ultra-tight integrated navigation system is used as the state equation of the visual assisted GNSS/ IMU ultra-tight integrated navigation system. Meanwhile, the pseudorange of SINS and GNSS, the difference of pseudorange rate, the platform misalignment angle of SINS, the position and attitude error of SINS and vision are used as the measurement information of the ultra-tight combination of GNSS/IMU assisted by vision. On this basis, the fuzzy control method is used to replace the traditional federated Kalman filter to fuse the information of the navigation structure of the two self-filters, and the navigation method is simulated and verified by C #. The simulation results show that the computational system performance is improved 52% by using the fuzzy control method compared with the traditional federal Kalman filter method, and the attitude error is significantly reduced in the ultra-tight integrated navigation system with visual assistance. When the GNSS signal is interfered by strong noise, the tracking accuracy of GNSS/IMU ultra-tight integrated navigation system assisted by binocular vision can effectively reduce the navigation error. And the position and velocity errors of the system are kept within 5.0m/s and 0.3m/s, respectively, which effectively solves the navigation problem of low altitudeaircraft in the case of GNSS signal occlusion or interference.