A Novel Method for Determination on Switch Timing Between Damping and Non-Damping Status of Strapdown Fiber Optic Gyrocompass

Abstract

It is necessary to locate the precise timing of switching into non-damping mode when the ship comes across zigzag maneuver, which helps avoid overshoot errors and maintain accuracy of ship's attitudes. In this paper, we propose a novel method to make the right decision on the damping/non-damping switch timing selection. Ship's in-motion data, collected by the gyrocompass system in advance, will first be pre-processed using wavelet denoising procedure and then treat as support vector machine (SVM) training in-put. Once the model is established, strapdown fiber optic gyrocompass (FOGC) can be equipped with the ability of self-judgment on when to cut off the alignment closed loops to become invulnerable and when to let it back online to remain stable by means of SVM classification schemes for switch timing recognition. Results show our method has better performance in the time of ships maneuver compared to the whole course damping network solution. Furthermore, transverse comparisons indicate our Wavelet-SVM method has better performance than BP neural network and traditional threshold method during maneuvering navigation process.

Keywords

• Strapdown gyrocompass
• alignment loops
• switch timing
• support vector machine
• wavelet denoising