Analysis of a Completely Integrated INS/GPS Navigation System for Re-Entry Vehicles

Erwin Lohnert, Bernd Eissfeller, Otto Wagner

Abstract:	The topic of this paper is to transfer the hybrid JNS/GPS technology from aviation applications to re- entry vehicles and to discuss its feasibility for the estimation of position, velocity and attitude during re- entry. Complete integration means that the INS is updated with GPS pseudorange, pseudodoppler and GPS attitude data. A Kalman filter is used to combine a linear dynamic model of the error propagation in an optical gyros strapdown system with updating GPS observations. The GPS receiver is assumed to be connected to four GPS antennas, which are fixed on the surface of the re-entry vehicle. Therefore, the GPS receiver is capable to provide additionally to position and velocity also attitude information, which leads to a complete integration of GPS and INS. The major error sources, the very high dynamics and kinematics of the re-entry vehicle as well as the radio blackout are taken into account. Based on a covariance analysis the simulation of the Kalman filter with GPS updates results in accuracies of? 140 m in position, + 0.5 m/s in velocity and 2 0.007 o in attitude for a high precision RLG-INS. The influence of different INS performance classes on the navigation errors are discussed. It is shown, that during a “loss of lock” the accuracy of navigation data depends to a high degree on the RLGs.
Published in:	Proceedings of the 7th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1994) September 20 - 23, 1994 Salt Palace Convention Center Salt Lake City, UT
Pages:	871 - 881
Cite this article:	Lohnert, Erwin, Eissfeller, Bernd, Wagner, Otto, "Analysis of a Completely Integrated INS/GPS Navigation System for Re-Entry Vehicles," Proceedings of the 7th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1994), Salt Lake City, UT, September 1994, pp. 871-881.
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