Strapdown inertial navigation system calibration

Abstract

The paper aims at improving the accuracy of the calibration of strapdown inertial navigation systems (SINS). The calibration is carried out using a 2-axial motion simulator. A new computational method is investigated for the calibration coefficients of the error models of accelerometers and gyroscopes of the strapdown inertial navigation system based on the errors of the system output signals. The modified navigation algorithms of the 3-channel strapdown inertial navigation system are used. The algorithms of the system orientation and navigation are generated using the kinematic Poisson's equations and the basic equation of the inertial navigation in the quaternion form. Damping links are introduced into the algorithms; they have been built based on the errors in the linear velocity computing and errors of the orientation angles computed as a difference between the system data and the motion simulator data. As a result, the vector and quaternion dependences are obtained to calculate the signals of the accelerometers and gyroscopes; they are used to calculate the instrumental errors and calibration coefficients of the error models. The increased calibration accuracy of the system is achieved by the reduction of the signals' noisiness of the accelerometers and gyroscopes after they have been processed with the modified algorithms and as a result of eliminating the symmetry requirement of the calibration coefficients in the opposite positions of the simulator as well as a result of the instrumental errors consideration for the motion simulator.