Inertial navigation employing common frame error representations

This paper explores a new paradigm for inertial navigation systems. Errors in filter applications using inertial navigation system equations have been previously defined from an abstract vector point-of-view. For example, the error in velocity has always been expressed using a straight difference of the truth minus the estimate without regard to each of the vector’s frame representations. In this paper an alternative vector state-error is defined using common coordinates over all vector error realizations, thereby providing a true-to- life representation of the actual errors. A modified extended Kalman filter is derived that employs the alternative vector state error representation. Simulation results are shown to assess the performance of the new filter design compared with the standard inertial navigation filter.