Specific Azimuth Self-Calibration of PIGA of Inertial Platform System

A method of calibration of the pendulous integrating gyro accelerometer (PIGA) of the inertial platform system (IPS) is proposed. By aligning the inertial measurement unit (IMU) with the specific azimuth of the geography coordinate frame, the gravity acceleration is measured by the PIGA at different horizontal angles within the east-west direction vertical plane, and the installation errors and the bias of the PIGA can be calibrated using total least-square estimation or recursive least-square estimation. The specific measurement position helps to suppress the error of the PIGA caused by the earth angular rate, and makes it easier to be compensated. Simulation and the IPS prototype based calibration experiments validated the precision and practicability of the proposed method. For the IPS equipped with quartz accelerometers as redundancy, when the IMU is stabilized in inertial space, the attitude matrix of the IPS's base can be estimated using the IPS's frame angle information and accelerometer output data. Align the IMU with the specific azimuth for calibration, and the online self-calibration of PIGAs can be implemented. The primary cause to decline the calibration precision and its solution are also analyzed.