New initial alignment method of carrier based inertial navigation system on swinging base

A new initial alignment method is studied to solve the problem of high-precision alignment of carrier based inertial navigation system (INS) on swinging base. Open-loop algorithm is designed to build a mathematical platform to isolate the swinging motion of the base, which can increase the signal to noise ratio of high accuracy carrier based INS measurement data during alignment, thus reduces alignment time and improves accuracy. Expressions of mathematical platform misalignment angles of the open-loop algorithm are derived and parameter identification method is used to pick-up the corresponding coefficients from angle measurements in order to identify and compensate gyro drifts and platform misalignment. Marine experiments show that the proposed method can achieve an alignment accuracy better than 0.0005°/h in 8 hours, thus can meet the high-precision alignment requirement of carrier based inertial navigation system on swinging base.