Research Of Single-axis Rotating Inertial Navigation System Algorithms For Underwater Vehicle

Rotational modulation technology is becoming a research topic in terms of the strap-down inertial navigation system (SINS). With the rapid development of the Fiber optical gyroscope (FOG), it is possible to develop a rotating inertial navigation system with low cost and high precision. A rotating inertial navigation system is equivalent to a strap-down inertial navigation system which is mounted on a rotating assembly with an angle measuring device. The navigation error can be compensated by rotational modulation to ensure the navigation accuracy of vehicle in a long term. Nowadays owing to its unique advantages, the FOG-based rotating inertial navigation system has been widely used. This thesis takes practical engineering applications as background. The rotational modulation technology is applied to strap-down inertial navigation system. The crucial techniques in single-axis rotating strap-down inertial navigation systems are studied. Eventually, the actual principle prototype is built and tested. The work of this thesis is focused on:1. The common coordinates and their transformation relation is given. The principle and structure of rotating inertial navigation system is analyzed, and the error equation of strap-down inertial navigation system with single-axis rotation is then deduced based on it. Meanwhile, principle of error compensation of single-axis rotating inertial navigation system is studied.2. Main types of errors for strap-down inertial navigation system are introduced. The various error effects under single-axis rotating inertial navigation system are analyzed, including the gyro drifts and accelerometer bias, scale factor error,s misalignment errors, dimension effect errors, and so on.3. The selection of the rotating shaft, the modulation effect impact of rotational rate and the evaluation guidelines of rotational motion scheme are analyzed. The error modulation effects of continuous re-versible rotation scheme and four-position switch-stop scheme are analyzed. Finally, a mathematical simulation model is established and the related simulation is carried out.4. A series of related navigation experiments based on real single-axis rotating inertial navigation system are conducted, including three-axis turntable experiments, roadster experiments, and so on. The feasibility of the schemes is verified.