In-flight line-of-sight sensor boresighting using GPS receiver data

A technique is presented to boresight a two-axis line-of-sensor, in-flight, using outputs from an inertially aided GPS receiver. This technique implements scalar Kalman filters in the sensor´s line-of-sight frame to estimate errors between a computed sensor line-of-sight and readouts available from the sensor while tracking a surveyed ground reference point. Compensations for INU attitude and position errors are applied in the computed line-of-sight prior to entering these scalar filters. The a priori knowledge of the INU attitude and position errors, available from the GPS receiver´s outputs, is used in applying the compensations. Monte Carlo simulation results are presented showing the boresight accuracies achieved using this technique based on a single encounter for several aircrafts, and improvements available from multiple encounters with the ground reference point for a single aircraft