Accelerometers Versa Gyros in Integrated Navigation Systems for Flexible Vehicles

Joerg F. Wagner and Thorsten Oertel

Abstract:	Integrated navigation systems are typically a special case of integrated motion measurement systems. Up to now, such systems model the vehicle as a single rigid body reflecting mainly classical navigation requirements. However, this does not fix coercively the concept of integrated navigation. Furthermore, systems based on classical rigid body models can show stability problems during phases of low vehicle dynamics. It is possible to avoid this effect by distributing navigation sensors over a large vehicle structure. On the other hand, in this case the assumption of a single rigid body is no longer valid, as the deformations cannot be neglected anymore. Nevertheless, determining the motion of large vehicles with additional mechanical degrees of freedom is possible if appropriate motion models and suitable sensor arrangements are available. Moreover, resulting navigation data describing additionally vehicle distortions can be an interesting basis for motion control and structural health monitoring as well. The basic idea of integrated navigation systems consists of blending complementary measurement principles like combining inertial sensors with GPS receivers. The kernel of integrated navigation systems is typically a Kalman filter estimating the unknown motion state of the vehicle. The filter needs a kinematical model for interpreting the sensor signals. This model comprises a vehicle motion part and an aiding part, which reflect the mechanical meaning of all measurements and which avoid using any mass, damping, or stiffness parameters of the vehicle structure considered. Based on the theory of integrated navigation systems the paper considers flexible structures for an integrated motion measurement. For this, the example of an elastic beam has been investigated. Especially, the paper compares the Kalman filter performance for different kinematical models using peripherally distributed accelerometers, gyros, and a combination of both sensor types. The results show firstly that expanding the principle of integrated navigation systems to flexible vehicles is possible with reasonable data quality and secondly that using gyros is preferable compared to accelerometers.
Published in:	Proceedings of the 2008 National Technical Meeting of The Institute of Navigation January 28 - 30, 2008 The Catamaran Resort Hotel San Diego, CA
Pages:	689 - 698
Cite this article:	Wagner, Joerg F., Oertel, Thorsten, "Accelerometers Versa Gyros in Integrated Navigation Systems for Flexible Vehicles," Proceedings of the 2008 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2008, pp. 689-698.
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