Abstract:When calibrating the Strapdown Inertial Unit with the three-axis turntable, it is necessary to lead the three-axis turntable to the north, which is used to accurately measure the angle of the Strapdown Inertial Unit with respect to the north direction of the earth. In order to reduce the heavy workload caused by looking for north reference, based on the study of traditional six position calibration method, a twelve position calibration method is designed. the twelve position flip arrangement is given, the error parameter model of Strapdown Inertial Unit device is established, and the equation for solving the error parameters is derived in detail, and the twelve position calibration method is verified through the experiments on a high precision three axis turntable. The results show that the twelve position calibration method can still calibrate the twenty four error parameters of Strapdown Inertial Unit device, and its accuracy is equivalent to that of the six position calibration method, as a result, the predict purpose has been achieved.