Sagem Defense Securite

Safran Electronics & Defense

Lionel Rosellini

Georges-Olivier Reymond

Mathieu Bresson

Hervé Lamarre

Yannick Foloppe

In a gyroscopic system, a vibrating gyroscope is controlled in gyrometer mode in a control loop. The control loop corresponds to at least one current control for an operating parameter. In the control loop, a modified control to be applied to the gyrometer for said operating parameter is obtained () by introducing a sinusoidal interference into the current control. Then, the modified control is applied () to the gyrometer as the current control. A resulting measurement value () is determined. A sinusoidal interference () is calculated as a function of said measurement value. Lastly, on the basis of the measurement value, it is decided () whether to repeat the previous steps on the basis of the sinusoidal interference last determined.

Calibration of vibrating gyroscope

The invention relates to a method for updating and/or for initializing, in a system comprising an image sensor oriented towards the horizon such as a pair of binoculars coupled to a geographical north seeker incorporating a gyrometer, a value representative of the orientation of the image sensor with respect to north, in which the shift of two images arising from the digital image sensor is determined at a first instant and at a second instant that are distinct so as to construct an item of information representative of an angular movement, and in which this angular movement information is utilized to: update the value of orientation of the image sensor;&#x2014;and/or to discriminate the movements of the image sensor with respect to the ground from the movements of the image sensor that are due to the rotation of the earth, in a process for initializing the value of orientation of the image sensor using a north seeker of gyroscopic or gyrometric type rigidly tied to the image sensor.

Method for updating a value of orientation with respect to north or for improving the initialization of such a value in an apparatus comprising an image sensor

A vibrating sensor having a base and an axisymmetrical resonator secured to the base. The base and the resonator are associated with electrodes connected to a control circuit via at least a first connection channel and a second connection channel with the electrodes being connected to one or other of the channels. The control circuit has excitation electronics and detection electronics and is arranged to control an excitation stage and a detection stage on each of the connection channels. The excitation stages and the detection stages have substantially identical respective durations, wherein the control circuit is arranged to perform the following sequence: excitation stage on the second connection channel; detection stage on the first connection channel; excitation stage on the first connection channel; detection stage on the second connection channel.

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Paris, France

Lionel Rosellini