Applying the principle of integrated navigation systems to estimating the motion of large vehicles

Combining inertial sensors and GPS has led to integrated navigation systems of a performance surpassing classical navigation requirements. A utilisation of this technology suggests itself which considers not only the classical movement of a small, rigid body but expands the application range also to large aircraft, space stations and suchlike. The signals generated on this basis are usable both for vehicle guidance and for structural control. The key element of such a generalisation is the kinematical model describing the vehicle motion: Until now, the mentioned restriction to rigid bodies is regular and considers only inertial sensors referring to a single vehicle point. A more general navigation system design considers, however, a specific model comprising additional degrees of freedom from structural distortions as well as spatially distributed sensors. This model is employed within an extended Kalman filter estimating the vehicle motion state of high resolution regarding time. In addition, the filter uses the signals of gyros, accelerometers, satellite navigation receivers, and structural sensors. For this purpose, the paper discusses firstly different variants of integrated navigation systems followed by a presentation of the advantage of spatially distributing satellite navigation antennas over the vehicle structure. Finally, the integrated system for a simple flexible aircraft structure is introduced.