An improved coarse alignment method applied to unmanned ships

Abstract

An improved coarse alignment method applied to unmanned ships during travel. An improved inertial system coarse alignment method with variable storage window length is proposed for the alignment of unmanned ships during travel. The corresponding vectors in different coordinate systems are constructed by changing the window length. For the traditional alignment algorithm between travels, Doppler counters are mostly used. Measuring the velocity of the moving target carrier body (v b ) and neglected items, using the attitude matrix estimated by the alignment algorithm to convert the navigation coordinate system (n system) velocity (v n ) into carrier coordinate system (b system) velocity (v b ), the angular velocity of the navigation coordinate system is converted to the angular velocity of the carrier coordinate system for iteratively estimating the attitude matrix. Compared with the previous alignment of the moving base based on the inertial system, this algorithm is closer to the INS equation of motion to the greatest extent, improves the utilization of measurement data, and can improve the accuracy and stability of the alignment of the unmanned ship. .

Description

technical field [0001] The invention relates to the technical field of surveying and mapping of unmanned ships, in particular to an improved rough alignment method applied to unmanned ships during travel. Background technique [0002] The coarse alignment of the strapdown inertial navigation system is to obtain an approximate attitude matrix within a certain period of time Prepare for the follow-up fine alignment work. When working at sea, unmanned ships will be affected by sea conditions such as wind, waves, and currents, and will perform six-degree-of-freedom movements: roll, pitch, yaw, heave, surge, sway, etc. Unmanned ships are no longer traditional Static base condition in the sense. At the same time, due to the needs of work, the unmanned ship may have to carry out navigation operations after being launched by the mother ship. In addition to the interference linear velocity and interference acceleration caused by external factors, it also has its own linear velocit...

AI Technical Summary

Problems solved by technology

For the alignment of the moving base during travel, many methods have been proposed in China. Among them, the external velocity reference is widely used to assist the alignment between travels. In order to ensure the alignment accuracy, the velocity is smoothed through a filter or compass horizontal alignment. , increasing the workload of coarse alignment

Images