Three-point calibration for long-endurance inertial navigation systems based on limited position observations and reverse navigation

Addressing the periodic oscillation errors and cumulative errors in inertial navigation position information caused by the equivalent gyro bias in long-endurance tri-axial rotating inertial navigation systems. We propose a three-point comprehensive calibration technique based on limited position observations and reverse navigation to correct the system's horizontal attitude and position information, as well as to compensate for the equivalent gyro bias. Firstly, the reverse navigation algorithm repeatedly uses the gyro and accelerometer data stored from the alignment phase to the correction point to correct the system's horizontal attitude and position information. Secondly, the long-endurance system obtains limited information from three position correction points, formulates equations for equivalent gyro bias and attitude errors, and employs reverse navigation and filtering algorithms to estimate and compensate for the equivalent gyro bias. Through long-endurance simulation and marine prototype tests, we have verified that the proposed algorithm can correct the long-endurance inertial navigation system's horizontal attitude and position information, compensate for the equivalent gyro bias, thereby suppressing periodic oscillation and cumulative errors in the navigation information, and improving the positioning accuracy of the tri-axial rotating inertial navigation system during long-endurance operations.