Objectives  In order to research the convergence characteristics and parameter setting of compass azimuth alignment better, and analyze the influence of gyro constant drift and initial azimuth error on the convergence time of gyrocompass azimuth alignment,

  Methods  the frequency domain response of gyro constant drift and initial azimuth error in the system was obtained by using the designed gyrocompass azimuth alignment system. Then the time domain response function was obtained by inverse Laplace transform, and the convergence time of the time domain function was analyzed.

  Results  The analysis results show that the convergence time of gyrocompass azimuth alignment is related to the designed second order damped oscillation period, and is also related to the gyro constant drift and the initial azimuth misalignment. The convergence of gyrocompass azimuth alignment is judged by the error band of 0.01°. When the gyro drift is less than 0.05(°)/h, the gyrocompass azimuth alignment will converge in 0.9 damped oscillation periods at most. When the initial azimuth misalignment is less than 5°, the gyrocompass azimuth alignment will converge in 1.4 damped oscillation periods at most. The smaller the two factors are, the faster the gyrocompass azimuth alignment converges. When both of them work together, the initial azimuth error plays a major role in the control of the convergence time, and the gyro constant drift has a little influence on the convergence time. At last, the correctness of the analysis results in this paper is verified by numerical simulation.

  Conclusions  The analytical method in this paper provides a theoretical reference for controlling the convergence time of the gyrocompass azimuth alignment and the parameter setting.