Alignment algorithms for boresight and instrument calibration of a gimballed sensor

Summary form only given. The authors present a practical application of an attitude match algorithm useful for correcting boresight errors of an airborne LOS (line-of-sight) tracking sensor system. In order to provide high-quality information to other sensor and/or weapon control system, the tracker must be accurately aligned to a common attitude coordinate frame. It operates by comparing computed attitude from a high-quality aircraft INU, with the attitude computed using a gimballed gyro package inside of the sensor system. The residual attitude differences measured during aircraft and gimbal maneuvers are a direct indication of mechanical misalignment, tracker initial attitude errors, gimbal biases, and gyro uncertainties, and are used in a Kalman filter to estimate these quantities. A detailed analysis of a transfer alignment and instrument calibration filter for a gimballed sensor has been carried out. A filter sizing study has been performed, and the sensitivity of the suboptimal filter to the unmodeled error states and the incorrectly modeled measurement noise and errors has been investigated