Laser Gyro Strapdown Inertial Navigation System For Automatic Calibration Technology,

In this paper, the continuous automatic calibration technology of laser gyro strapdown inertial navigation system (LSINS) is studied. In LSINS, since the inertial sensors are direct mounted on the body, the sensors endure the angle motion, the inertial sensors' error of strapdown system is much than the error of platform system. Error compensation is an efficient way to enhance the accuracy of navigation, but error calibration is the precondition of error compensation. Traditional system grade calibration uses the velocity errors as the Kalman filter measurements, it has the disadvantages as the lack of measurements, large burden of calculation, etc, and so it is hard to use it in project. The continuous automatic calibration technology is a new way to calibrate the strapdown inertial navigation system, which uses the high accuracy three-axis turntable; it has the advantages such as high accuracy, high efficiency, flexibility of the calibration trajectory. Using the continuous rotation of turntable, the dimension effect parameters can be calibrated.In this paper, the error models of laser gyros and accelerometers are studied, the considered errors include laser gyros' cross-axis coupling factors, scale factor errors and constant biases, accelerometers' cross-axis coupling factors, scale factor errors, second order errors and biases. And the cause and compensation of dimension effect is studied. Two Kalman filters are designed to calibrate the errors of gyros and accelerometers.The design of calibration trajectory is the key of the continuous automatic calibration technology. The purpose is to design an optimum trajectory of turntable, excite the system error source, and isolate the error parameters. In this paper, the principle of the selection of calibration trajectory is analyzed, an available trajectory is get through simulation.The mechanization, error models, Kalman filters and trajectory are simulated in Simulink, and the simulation result is presented. And it shows that this technology is feasible, and has the practicability in engineering.And the proving experiment has done using the two-axis turntable. For its function is limited, only some parameters can be calibrated, but the error compensation effect indicates that the continuous automatic calibration technology is feasible.