Design of rotation strategy for dual-axis laser gyro inertial navigation system

Abstract For dual-axis rotational inertial navigation system, device errors can be compensated by using rotational modulation techniques and 16-position rotation scheme is currently the mainstream modulation scheme. The arrangement of rotation sequence directly impacts the performance of error modulation and must be meticulously designed. This paper analyzes the error characteristics of laser gyro inertial navigation systems, focusing on minimizing the oscillation of the platform misalignment angle induced by gyro misalignment angle within a single modulation period, and proposes an improved 16-position rotation scheme based on conducting the first study to analyze the impact of the sign of the gyro misalignment angle on error compensation. Through simulations and experiments, the proposed improved scheme is compared with a widely employed classic 16-position rotation scheme. The results demonstrate that, when the misalignment angles of the two gyroscopes studied have different signs, the improved 16-position scheme significantly enhances accuracy over the classic 16-position scheme. When the misalignment angles of the two gyroscopes studied are of the same sign, the improved 16-position scheme maintains comparable navigation accuracy to the classic 16-position scheme. Furthermore, this strategy can completely mitigate the impact of the studied gyroscopic installation misalignment angles on navigation accuracy, ensuring high-precision navigation performance of the system without the need for recalibration, even when significant changes in the installation misalignment angles occur due to factors such as temperature, environment, and carrier motion. This study not only enhances navigational accuracy but also holds significant research implications and practical value for extending calibration cycles or even achieving calibration-free operation.