Abstract: The invention relates to a navigation system for aircraft comprising inertial sensors, a GNSS receiver and potentially a baro-altimeter. The measurements from the inertial sensors are hybridized with the code and phase measurements from the receiver within a main Kalman filter and, possibly, secondary filters. The said measurements are corrected for several types of errors, notably those due to the passage of the satellite signals through the ionospheric layers. The precision of the determination of the position of the aircraft is greatly improved, both in the horizontal plane and in the vertical direction. This is also the case for the corresponding protection radii, which allows margins to be created in order to satisfy the integrity constraints for the navigation solution.

Abstract: Hybrid inertial system onboard a mobile carrier comprising an inertial measurements unit, at least one platform for integrating inertial data, at least one exterior sensor and a multi-hypothesis hybridization filter, the said system being characterized in that the said hybridization filter implements at least the following steps: an initialization step performing the generation of a plurality of state vectors an update step executing, for each of the said state vectors, the phase of readjusting an extended Kalman filtering a propagation step executing, for each of the said state vectors, the phase of propagation of an extended Kalman filtering a step of determining the likelihood qit of the said updated state vector a step of calculating inertial corrections.

Abstract: The invention relates to a navigation system for aircraft comprising inertial sensors, a GNSS receiver and potentially a baro-altimeter. The measurements from the inertial sensors are hybridized with the code and phase measurements from the receiver within a main Kalman filter and, possibly, secondary filters. The said measurements are corrected for several types of errors, notably those due to the passage of the satellite signals through the ionospheric layers. The precision of the determination of the position of the aircraft is greatly improved, both in the horizontal plane and in the vertical direction. This is also the case for the corresponding protection radii, which allows margins to be created in order to satisfy the integrity constraints for the navigation solution.

Abstract: Hybrid inertial system onboard a mobile carrier comprising an inertial measurements unit, at least one platform for integrating inertial data, at least one exterior sensor and a multi-hypothesis hybridization filter, the said system being characterized in that the said hybridization filter implements at least the following steps: an initialization step performing the generation of a plurality of state vectors an update step executing, for each of the said state vectors, the phase of readjusting an extended Kalman filtering a propagation step executing, for each of the said state vectors, the phase of propagation of an extended Kalman filtering a step of determining the likelihood qlt of the said updated state vector a step of calculating inertial corrections.

Abstract: To improve the accuracy of altitude measurement, the inertial unit (C_INERT) is associated with a radiosonde supplying a height (HAUT_ALT) of the aircraft relative to the ground and a terrain database (DTED) supplying an altitude of the ground (ALT_GND) at the horizontal position (POS_HOR_HYB) of the aircraft delivered by the inertial unit. The inertial unit supplies an altitude (ALT_HYB) which is corrected based on the values supplied by the radiosonde and the terrain database. A radius of protection (RPalt_hyb_cor) of the altitude thus corrected is computed. For this computation of protection radius, particular use is made of a computation of the altitude dispersion of the terrain around the horizontal position of the aircraft, in a circle delimited on the basis of the radius of protection of the horizontal position (RPpos_hor_hyb), supplied by the inertial unit at the same time as the horizontal position.