1. A hybrid navigation device for a vehicle, comprising: at least one auxiliary sensor (DET 1 ) adapted to deliver at least one auxiliary signal representative of an auxiliary navigation parameter of the vehicle, and a plurality of hybrid navigation systems (INH 1 , INH 2 ), each hybrid navigation system comprising at least one inertial navigation system comprising at least one inertial measuring unit (IMU- 1 , IMU- 2 ), said inertial measuring unit (IMU- 1 , IMU- 2 ) being adapted to deliver at least one signal representative of an inertial measurement, and each hybrid navigation system comprising at least one calculator (CALC-H 1 , CALC-H 2 ) configured in such a manner to hybridize said at least one signal representative of an inertial measurement with said at least one auxiliary signal, to form a hybrid signal at the output of each hybrid navigation system (DATA 1 , DATA 2 ), characterized in that: said hybrid navigation device comprises a module (MOD) for the detection of good operating condition and the weighting of said hybrid navigation systems (INH 1 , INH 2 ), said module (MOD) being configured in such a manner to receive, on the one hand, said at least one auxiliary signal, and on the other hand, said hybrid signals (DATA 1 , DATA 2 ) at the output of each hybrid navigation system (INH 1 , INH 2 ), respectively, and to deduce therefrom at least one indicator of good operating condition (STATUS) and a weighting coefficient for each hybrid navigation system (INH 1 , INH 2 ), said weighting coefficient being respectively calculated as a function of a likelihood of the residue between said hybrid signal (DATA 1 , DATA 2 ) and said auxiliary signal, and said module (MOD) being configured in such a manner to calculate a weighted hybrid signal (DATAOPT) as a function of said hybrid signals (DATA 1 , DATA 2 ) and of the weighting coefficients of each hybrid navigation system, respectively.