A method for locating a device comprising a fusion step of data arising from a first image sensor and from a motion and/or position measuring module, the said first sensor and the said motion and/or position measuring module being integral and forming a device, characterized in that it comprises at least the following steps: • A first step consisting of acquiring several points on the images in order to define a current pose p t c of the device image camera and motion and/or position measuring module for a given instant t, • A prediction step of the predicted pose p ^ t k of the device camera and motion/position sensor for the same given instant t and using the measurements from the motion and/or position measuring module, • A step where we determine an associated constraint ε k for the sensor k of the device camera c and sensor k, • A step where we automatically determine a weighting coefficient λ t of the said constraint, • An estimation step of the current pose p t of the said device, • A step of simultaneous optimization of the poses p t' of the device camera + sensor by the bundle adjustment technique using the following cost function: E BA X t, Z t = ∑ t ' = t − M t − N ε c 2 p t ′ s, z t ′ c + ∑ t ' = t − N − 1 t E p p t ′ s, Z t where ( p t- M,....p t- N) corresponds to fixed poses and ( p t- ( N-1),p t- ( N-2),p t) poses of the camera to refine with E p x t, Z t = ε c 2 x t, z t c + λ t 2 ε k 2 x t, z t k ∘ ε c 2: reprojection errors of the scene in the images ∘ x t = [ ps] the pose of the device and the scene ∘ z t c: = the observations of the scene detected in the image of the camera c at the instant t ∘ Z t = z t c z t k set of all the measurements for all the camera c sensors and of the sensors k of motion and/or position module at an instant t. • A first step consisting of acquiring several points on the images in order to define a current pose p t c of the device image camera and motion and/or position measuring module for a given instant t, • A prediction step of the predicted pose p ^ t k of the device camera and motion/position sensor for the same given instant t and using the measurements from the motion and/or position measuring module, • A step where we determine an associated constraint ε k for the sensor k of the device camera c and sensor k, • A step where we automatically determine a weighting coefficient λ t of the said constraint, • An estimation step of the current pose p t of the said device, • A step of simultaneous optimization of the poses p t' of the device camera + sensor by the bundle adjustment technique using the following cost function: E BA X t, Z t = ∑ t ' = t − M t − N ε c 2 p t ′ s, z t ′ c + ∑ t ' = t − N − 1 t E p p t ′ s, Z t where ( p t- M,....p t- N) corresponds to fixed poses and ( p t- ( N-1),p t- ( N-2),p t) poses of the camera to refine with E p x t, Z t = ε c 2 x t, z t c + λ t 2 ε k 2 x t, z t k ∘ ε c 2: reprojection errors of the scene in the images ∘ x t = [ ps] the pose of the device and the scene ∘ z t c: = the observations of the scene detected in the image of the camera c at the instant t ∘ Z t = z t c z t k set of all the measurements for all the camera c sensors and of the sensors k of motion and/or position module at an instant t. ∘ ε c 2: reprojection errors of the scene in the images ∘ x t = [ ps] the pose of the device and the scene ∘ z t c: = the observations of the scene detected in the image of the camera c at the instant t ∘ Z t = z t c z t k set of all the measurements for all the camera c sensors and of the sensors k of motion and/or position module at an instant t.