Satellite navigation method with satellite failure detection by statistical processing of cross-innovation
AssigneeSafran Electronics & Defense
InventorsYves Becheret, Maxime Nguyen
Life of this patent
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Abstract
A navigation method using a plurality of pseudo-measurements obtained from satellite signals, the method implementing a Kalman filter bank having a main filter calculating a main navigation solution from the pseudo-measurements originating from satellites, and sub-filters each calculating a secondary navigation solution, and at least one innovation of the pseudo-measurements for each non-excluded satellite and a cross-innovation. An indicator is determined from the sensitivity of the cross-innovation to the innovations of the non-excluded pseudo-measurements. A corresponding navigation system and to a vehicle equipped with same are also provided.
Claims11
A method for navigation on the basis of a plurality of pseudo-measurements obtained from satellite positioning signals each originating from a satellite, using a Kalman filter bank comprising a main filter calculating a main navigation solution from pseudo-measurements obtained from satellites and sub-filters each calculating:
- a secondary navigation solution on the basis of pseudo-measurements obtained from satellites, excluding therefrom the pseudo-measurements obtained from at least one satellite, and at least
- a pseudo-measurement innovation for each remaining satellite,
- a cross-innovation reflecting the difference between an observation corresponding to the pseudo-measurement excluded by the sub-filter and an a posteriori estimate of said observation obtained from the secondary navigation solution produced by the sub-filter,
- wherein the method comprises the steps of:
- determining a sensitivity equation reflecting a sensitivity of the cross-innovation to non-excluded pseudo-measurement innovations;
- extracting coefficients for the sensitivity (Csi) of each sub-filter to pseudo-measurements for each satellite (i) from the sensitivity equation;
- forming a satellite failure indicator on the basis of the sensitivity coefficients (Csi) for each sub-filter to the pseudo-measurements for each satellite (i) and comparing the satellite failure indicator with a threshold in order to determine whether the satellite has failed.
Dependencies are inferred from the claim text.