Research On The Method For Systematic Calibration And Alignment Of Laser Strapdown Inertial Measurement Unit

Inertial navigation is the process of continuously determining the position,velocity and attitude of a vehicle,relying solely on the information provided by rigidly-mounted accelerometers and gyros.This paper focuses on the method for systematic calibration and alignment of Laser Strapdown Inertial Measurement Unit(LSIMU).The systematic calibration is to identify the parameter errors of the accelerometer and gyroscope calibration with the navigation calculating error of the SINS.The high accuracy calibration of the SINS can be realized with only a low accuracy equipment,because the demand for the systematic calibration of the equipment accuracy is not high compared to the discrete calibration,so research on the systematic calibration has an important significance.The calibration models of the accelerometer and gyroscope are introduced first.An accurate calibration method using low precision turntable is presented,and the principle of the position arrangement in the calibration process is analyzed in detail.The initial alignment of SINS is the premise of the navigation process,which is intended to provide the initial value of the Direction Cosine Matrix required for the process.The initial alignment is divided into two processes: coarse and fine process.The coarse alignment on static base using double-vector method is briefly introduced.The coupling existing between the inertial sensor biases and Kalman filter error state variables is investigated,providing the basis for selection of state quantity.The methods based on Linear Kalman Filter and Extended Kalman Filter are derived.