Time-varying parameters based gyrocompass Alignment for marine SINS with large heading misalignment

Gyrocompass alignment algorithm is a fine alignment technique based on gyrocompass effect and loop feedback control theory. Conventional strapdown gyrocompass alignment methods are based on the assumption that the system has a small heading misalignment angle. However, a large heading misalignment angle would exist during the alignment duration under some conditions, especially for marine strapdown inertial navigation system (SINS). This paper proposed a time-varying parameters based gyrocompass alignment method to solve this problem. Error model of gyrocompass alignment with large heading misalignment error is presented and an appropriate multi-parameter setting is given, a proper scenario for parametric switch is also derived. Simulation and experimental results show that the proposed method has better alignment performance than conventional ones when the system has a large heading misalignment angle.