Dual Axis Rotary Self-Calibration of Fiber Optic SIMU

Inertial unit errors are the main influencing factors of the strapdown inertial navigation accuracy. It is necessary to accurately calibrate the inertial unit errors (installation errors, zero position errors and scale factors) before shipment of inertial navigation equipment. However, after the inertial navigation equipment is delivered for use, the system parameters may change according to the service environment and the operating time, and the inertial unit may be subject to the successive start error. In order to ensure that the inertial navigation equipment can maintain a relatively high navigation and positioning accuracy for long, the system parameters (installation errors, zero position errors and scale factors) must be recalibrated. If the conventional discrete calibration is applied, the inertial navigation equipment or the inertial measurement unit must be removed from the vehicle and the parameters must be calibrated through a high precision three axis turntable. This increases the cost of repair and maintenance of equipment, makes it difficult to provide warrant and requires very good skills of operators. A dual axis rotary mechanism is added to the strapdown inertial navigation can improve the observability of the system state variables, and the installation errors, zero position errors and scale factors of inertial units can be calibrated with Kalman filtering, thus achieving the systematic calibration of the inertial navigation equipment.