MIMU/GPS precise integrated navigation method aided by heading information

In order to achieve high precision and low cost navigationwith fewer than four satellites, MIMU/GPS precise integrated navigation method aided by heading information is proposed. The micro inertial measurement unit (MIMU) and Global Positioning System (GPS) are chosen to construct MIMU/GPS integrated navigation system. To solve the problem of being unable to realize the positioning function when with <4 satellites, the position information calculated by the output of MIMU and the ephemeris data output of GPS are utilized to construct the equivalent pseudo range, then this equivalent pseudo range and the pseudo range output from GPS are chosen as one of the observations of integrated navigation. To solve the problem that the heading error of integrated navigation islarge or even divergent, the horizontal velocities of GPS are utilized to calculate the pseudo heading angle, then this pseudo heading angle and the heading angle calculated by the output of MIMU are chosen as the other observation. Kalman filter is adopted to design the integrated navigation filtering algorithm. Experimental results show that, when the number of satellites is less than four repeatedly, the position accuracy of the integrated navigation method is±10.3m(3σ), the horizontal attitude accuracy is±20.1'(3σ), and the heading accuracy is±19.5'(3σ). Therefore, this method effectively solves the problem of precise navigation when the number of satellites is less than four, and the heading accuracy is improvedgreatly. In particular, the navigation filtering can converge quickly in the case with large misalignment angles. © 2018, Editorial Department of Journal of Chinese Inertial Technology. All right reserved.