Time Synchronization Errors in GPS-Aided Inertial Navigation Systems
The effects of time synchronization errors in a GPS aided Inertial Navigation System (INS) are studied in terms of the increased error covariance of the state vector. Expressions for evaluating the error covariance of the navigation state vector - given the vehicle trajectory and the model of the INS error dynamics-are derived. Two different cases are studied in some detail. The first case considers a navigation system in which the timing error is not included in the integration filter. This leads to a system with an increased error covariance and a bias in the estimated forward acceleration. In the second case, a parameterization of the timing error is included as a part of the estimation problem in the data integration.