A 3D target model expressed in intrinsic coordinates will be developed in this article. The frame used is the Frenet-Serret frame, that is a practical frame to represent the commands a pilot can have on his aircraft for instance. A quite accurate description of the possible motions of an aircraft is to assume the commands are piecewise constant. Once the target model is derived, a filtering algorithm is needed to perform state estimation. As the target model is not expressed in a vectorial space, but rather in a Lie group setting, a novel algorithm, based on results from the inertial navigation field has to be established. This new filter is called the Invariant Extended Kalman Filter (IEKF).