Coupling Angle Vibration Model and Error Suppression Method for INS

In order to avoid the decrease in navigation accuracy and damage to system brought by severe vibration, airborne, and missile borne, Inertial Navigation System (INS) is often mounted with vibration isolators. However, if the elastic center of the vibration damping system does not coincide with the center of mass of the INS, when only linear vibration input is available, the introduction of the shock absorber will produce angular vibration, and angular vibration and linear vibration will be coupled, that is, coupled angular vibration will be generated, resulting in additional navigation errors. This article aims at solving this problem for a rotational INS (RINS). First, to theoretically analyze the cause of coupled angular vibration, the six degree of freedom coupled angular vibration model of INS is derived. We also analyze the relationship between the misalignment angle of vibration isolators and vertical angular vibration. Second, a vibration suppression method for RINS is proposed. We use the angular velocity measured by the gyro as feedback to control the rotational gimbals of RINS to isolate the coupled angular motion. Experimental results show that the velocity oscillation of RINS caused by the vibration is greatly suppressed and thus proves the validity of the proposed method.