A method, a system, and a computer program product for tracking an object moving relative to a moving platform, the moving platform moving relative to an external frame of reference. The system includes An inertial sensor for tracking the object relative to the external reference frame, a non-inertial sensor for tracking the object relative to the moving platform, and a processor to perform sensor fusion of the inertial and non-inertial measurements in order to accurately track the object and concurrently estimate the misalignment of the non-inertial sensor's reference frame relative to the moving platform.