US 6,982,669 B2
Hybrid inertial navigation system with improved integrity
Jacques Coatantiec, Bourg les Valence (France); and Patrice Guillard, Valence (France)
Assigned to Thales, Neuilly sur Seine (France)
Appl. No. 10/488,941
PCT Filed Sep. 24, 2002, PCT No. PCT/FR02/03258
§ 371(c)(1), (2), (4) Date Mar. 09, 2004,
PCT Pub. No. WO03/029755, PCT Pub. Date Apr. 10, 2003.
Claims priority of application No. 01 12546 (FR), filed on Sep. 28, 2001.
Prior Publication US 2004/0239560 A1, Dec. 02, 2004
Int. Cl. H04B 7/185 (2006.01)
U.S. Cl. 342—357.14 4 Claims
OG exemplary drawing
 
1. A navigation system, comprising:
an inertial navigation platform hybridized with at least one satellite based positioning receiver, the inertial platform providing position information resulting at least in part from accelerometric and gyrometric measurements, and the receiver providing pseudo-distances representing the distance between the receiver and satellites, the receiver comprising, for each channel of the receiver, a digitally phase controlled oscillator slaved to the phase of a carrier of a satellite signal corresponding to this channel;
wherein the navigation system provides hybrid position values resulting from a combination of numerical position data originating from the platform and numerical data originating from the receiver;
a means of estimating a new hybrid position on the basis of an observed deviation between pseudo-distances measured by the receiver between the receiver and each one of said satellites and corresponding distances computed by the inertial platform between the platform and said each one of said satellites, this means comprising a digital filter, of Kalman filter type, allowing the prediction of a deviation and the matching of the filter as a function of the comparison between the observed deviations and predicted deviations;
wherein in the digital filter, the distance increment from one measurement instant to the next instant, between a pseudo-distance previously measured by the receiver on a satellite axis and a new pseudo-distance measured by the receiver on said satellite axis, is the phase variation of the digital oscillator between the two measurement instants, this variation being referred to distance along said satellite axis.