Influences of Gyro Biases on Ship Angular Flexure Measurement

For ship angular flexure measurement based on the ring laser gyro units, an attitude matching method has been recently developed to take advantage of the smoothing effects of the attitude updating. For the attitude matching method, the influences of gyro biases have been assessed analytically. Strict derivation has proved that ship angular flexure is independent of the common gyro biases of the two units. The accumulation of the attitude error, arising from the gyro bias difference, may result in the nonlinearity error, degrading ship flexure measurement significantly. Thus, the feedback mechanism has been proposed. Numerical simulations show that, with feedback mechanism, the fixed gyro biases may have little influence on ship angular flexure measurement, while the random gyro biases may be slightly coupled with the nonlinear variations of the quasi-static flexure.