FR2607915A1 - FLYING GUIDANCE SYSTEM - Google Patents

Abstract

FLYING MACHINE GUIDANCE SYSTEM INCLUDING AN OPTICAL GUIDING BEAM PROJECTOR AND OPERATING ACCORDING TO THE IMAGE FIELD MODULATION BEAM GUIDING PROCESS. A PHASE 2 DIAPHRAGM IS MOBILE IN STEP 1 OF THE LASER RAY. THE PHASE 3 PROFILE OF THIS DIAPHRAGM IS CONVERTED TO PROFILE 7 OF AMPLITUDE OR INTENSITY IN THE IMAGE 11 OF THE OPTICAL 100 OF THE PROJECTOR.

Description

The invention relates to a flying cuidaae system.

  guidance of a flying object by means of an optical guide beam projector, operating according to the image field modulation beam guidance method. Such flying machine guidance systems are known in different embodiments. In many cases, they have taken the place of image scanning guide beam systems, because they guarantee a location of the flying object with great precision, with a relatively reduced technical expense. These guide beam systems make mirrors and high-frequency rotating scanning prisms superfluous as well as the synchronizations between the different degrees of scanning freedom,

  and furthermore, the bandwidth of the signals may remain reduced.

  However, the image modulation methods used on these systems have the great disadvantage that only a small intensity of the guide beam is available, which is due to the large opening angle of the guide beam cone, the entire field visual being illuminated simultaneously. This drawback is further accentuated by the fact that a significant part of the optical transmission power - typically even 50% - is absorbed or reflected by the impermeable zones of the modulator diaphragm and

  therefore cannot be used for signal transmission.

  The object of the present invention is to eliminate the drawbacks of the state of the art for the guidance systems of the flying machine mentioned at the beginning, and to create a system of a guide beam or all of the radiation power. of the light source can be used for the formation of the spatial beam sample

guide. -

  This object is achieved in the case of a system for guiding a flying machine by means of an optical guide beam projector, operating according to the method of guidance on beam with image field modulation, in that a phase diaphragm is movable -2- as a modulator diaphragm in the path of the laser beam, the phase profile of this diaphragm being converted into an amplitude or intensity profile in the image plane of the optics at

  projector. The description below explains an example of

  embodiment the configuration and operation of which are sketched by the figures in the drawing, in which FIG. 1 schematically represents a configuration of the optics of the guide beam projector, FIG. 2 represents a diagram concerning the intensity modulation for each phase variation, and FIG. 3 represents a schematic sketch for the conversion of a phase profile of rectangular shape into an intensity profile. Figure I represents an exemplary embodiment of the optics 100 of the guide beam projector, or according to the phase contrast method known in the ground, the phase profile 3, imparted to the optical laser beam I by the phase diaphragm , is converted without substantial power losses into an amplitude or intensity profile 7. The phase 2 diaphragm can for example be a transparent glass or germanium plate with an optical thickness 2a depending on the place of use, this plate being lit in a coherent manner and thus using all of the radiation power of the light source for the formation of the spatial sample of the guide beam. Appropriate fixing of the optical thickness profile 2a of both the phase diaphragm 2 and the phase plate 5, arranged in the Fourier plane of the objective, produced in the Image II plane (field lens 6) a profile of amplitude or intensity 7 contrast and fully modulated. That is to say that the phase profile 3, produced by the phase 2 diaphragm disposed mobile in the path of the beam, is converted in the image plane II into intensity profile 7 and emitted by

the projection lens 8.

  If the phase diaphragm 2 performs an appropriate movement in a plane perpendicular to the radiation axis 12, the intensity profile 7 of the guide beam 1 also moves. A fixed receiver can now determine, from the module signal

  received, the position thereof in the guide beam cone.

  Figures 2 and 3 show the conversion of a rectangular phase profile to an intensity profile so clearly

  that additional explanations seem superfluous.

  It remains to be mentioned that the optical thickness profile 2a of the phase diaphragm 2 and of the phase plate 1 0 (A = wT / 2) 5 can be produced for example by the application of a dielectric layer of a structure determined on a flat blade, using

  epitaxial and photolithographic processes.

  This steering system guidance system allows you to generate intensity samples without the usual transmission losses at the diaphragm structure. However, with the same power of the light source, we obtain a ratio

  much better signal / noise on the receiver.

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Claims (7)

Claims   1. System for guiding a flying object by means of an optical guide beam projector, operating according to the method of beam guiding with image field modulation, characterized in that a phase diaphragm (2) is has mobile as a modulator diaphragm in the path (1) of the laser beam, the phase profile (3) of this diaphragm being converted into a profile (7) of amplitude or intensity in the image plane (11) optics (100) of the projector.   2. Flying device guidance system according to claim 1, characterized in that the phase diaphragm (2) is constituted by a transparent plate, for example made of glass or germanium, with   an optical thickness profile (2a).   3. Flying device guidance system according to claim 1 or 2, characterized in that the optics (100) of the guide beam projector 5 present in the object plane (9) the phase diaphragm (2) mobile and the lens (4) arranged after this for the intermediate image, and that a phase plate (5) is arranged in the Fourier plane (10) and a field lens (6) in the plane picture (11).   4. Flying device guidance system according to any one of   claims 1 to 3, characterized in that the modulation quality   and the contrast of the amplitude or Intensite profile (7) can be determined by the optical thickness profile (2a) chosen from the   phase diaphragm (2) and phase plate (5).   2 5 5. Flying device guidance system according to any one of   claims 1 to 4, characterized in that the importance of the   intensity modulation (intensity profile 7) in the image plane (11) can be determined by the phase variation of the radiation (1) in the object plane (9).   6. Flying device guidance system according to any one of   Claims 1 to 5, characterized in that the phase diaphragm   - 5- (2) is movable in a plane perpendicular to the axis of radiation (12).   7. Flying device guidance system according to any one of   Claims 1 to 6, characterized in that the thickness profile   (2a) optics of the phase dlaphragm (2) is produced by the application of a dielectric layer of a determined structure on a plane plate by means of epitaxial or photolithographic methods.