Constrained H-infinity estimation algorithm for the course-adaptive model of electromagnetic controlled gyrocompass
带约束的电罗经航向自适应模型H∞估计算法

External interferences to the naval vessel in cruise, such as the wind, waves, swing and so on, bring about errors in course-indication of the electromagnetic controlled gyrocompass. These errors become more serious when the ship is in mobile actions. Moreover, the output of the electromagnetic controlled gyrocompass is not only volatile, but also in lag of time to the practical course. To reduce the course-error and improve the output accuracy of the electromagnetic controlled gyrocompass, we first derive the standard motion-equation for the principal axis of the electromagnetic controlled gyrocompass and consider it the ideal constraint. Secondly, we model the recorded field-data and predict it based on the self-adaptive four-parameter estimation method. Thirdly, we combine the H-infinity estimation theory with the steepesttracking-differentiator to determine an appropriate H-infinity error-estimation multiplier by solving the Riccati equation, and design the constrained H-infinity estimation algorithm. Finally, the comparison of the obtained result with the recorded field-data indicates that this algorithm is capable to provide a stable output.