Research and Experiment on System Level Calibration Method of Fiber Optic Strapdown Inertial Navigation System

An analysis is made to the zero bias, installation errors and scale factor propagation laws of a fiber optic strapdown inertial measurement unit from the systematic perspective, aiming to solve the problem that a certain type of fiber optic strapdown inertial navigation system requires a high precision turntable and is affected the rubber shock absorber in the conventional discrete calibration. A four-position rotation stop is conducted around X, Y, Z gyro sensitivity axes to excite the error parameters of fiber optic gyros and accelerometers, thus achieving systematic calibration of the fiber optic strapdown inertial measurement unit. By comparing with the conventional discrete calibration method with gyro rate calibration and twelve-position calibration of accelerometers, an undamped navigation swing test of the same batch is carried out on the calibrated error parameters. The test indicates that when the navigation test is performed with the systematic calibration results, the velocity errors, position errors and positioning error output by the system are smaller than those derived from the navigation test with the discrete calibration results.