Stabilized multispectral sighting system

• US 6,108,133 A
• Filed: 06/15/1998
• Issued: 08/22/2000
• Est. Priority Date: 06/16/1997
• Status: Expired due to Fees

• Current Assignee: Sagem SA (Safran SA)
• Original Assignee: Sagem SA (Safran SA)
• Inventors: Broekaert, Michel, Encaoua, Serge, Joffre, Jacques, Buatois, Fabrice
• Primary Examiner(s): NGUYEN, THONG Q
• Application Number:
  US09/094,586
• Time in Patent Office: 799 Days
• Field of Search: 359/554-557, 359/201, 359/203, 359/220-221, 359/223, 359/226, 359/872-874, 359/876, 359/900, 250/203.5, 250/203.6, 250/203.7, 396/52-55
• US Class Current: 359/556
• CPC Class Codes: G02B 27/64 Imaging systems using optical elements for stabilisation of the lateral and angular position of the image

Abstract

The device has a stabilization mirror that is angularly steerable about two mutually orthogonal axes, and an optical system for splitting an incoming light beam into at least two channels corresponding to different wavelengths. The stabilization mirror is steerable about a first axis (L) on internal equipment that is itself steerable about a second axis (I) orthogonal to the first and intersecting in an assembly that is steerable on a support about a third axis (C). A servo-control system has a gyroscopic sensor tied to the mirror and controlling steering motors. The system further includes, upstream from the stabilization mirror, and on the path of an incoming beam, a purely catoptric optical system that is stabilized, giving the inlet beam a size on the mirror that is smaller than the size of the inlet pupil of the system.

Claims

1. A stabilized sighting system having:

a purely catoptric optical input system located on a path of an incoming light beam and mounted for rotation about a first axis on an internal equipment;

a sight stabilization mirror operatively associated with said optical input system for rotation therewith with a reduction ratio of 1/2;

first means for steering said stabilization mirror and optical input system about said first axis on said internal equipment;

second means for steering said internal equipment with respect to an external equipment about a second axis orthogonal to said first axis and intersecting said first axis;

third means for steering said external equipment with respect to an external assembly about a third axis coaxial with the second axis; and

fourth means for steering said external assembly on a support about a fourth axis;

each of said first, second, third and fourth axis having motor means; and

a servo-control system including a gyroscopic sensor associated with said optical input system and controlling said motor means;

said optical input system giving the incoming beam a size on the stabilization mirror that is smaller than a size of an inlet pupil of the optical input system.

2. A system according to claim 1, wherein the catoptric optical system comprises a telescope having an inlet concave mirror of large diameter and a convex mirror of smaller diameter delivering, from said incoming beam, an outlet beam that is converging on the stabilization mirror.

3. A system according to claim 2, having a deflection mirror carried by the external assembly and steering the beam received from the stabilization mirror to a channel parallel to the circular axis and including lenses constituting an afocal system with the telescope.

4. A system according to claim 3, wherein the deflection mirror includes a small zone in the form of a dichroic plate allowing an the emitted laser beam to pass for telemetry or for laser illumination, said laser beam having a very narrow field and following a separate channel through a side plate and then, after being transmitted through an dichroic portion of the deflection mirror, following a common channel, while occupying a small portion of its pupil.

5. A system according to claim 2, wherein said concave mirror has a central opening of diameter that corresponds to occultation by the convex mirror, and the internal equipment is displaceable through more than 180°

about the internal elevation axis to leave free an access passage for an inlet beam to a second optical system, of angular field greater than that of the telescope, and located upstream from the stabilization mirror, and the stabilization mirror is movable through 90°

to reflect a beam that is incoming through a porthole to a bending mirror.

6. A system according to claim 5, wherein said optical system further comprises a deflection mirror placed to reflect the beam coming from the stabilization mirror on a direction parallel to the lateral axis towards a dioptric system constituting another afocal system with a second optical system for obtaining other fields, which are generally larger.

7. A system according to claim 5, wherein the bending mirror is constituted by a dichroic plate for separating the incoming beam into 1.06 μ

m, 1.54 μ

m or 2 μ

m channels.

8. A stabilized sighting system having:

an optical block comprising a purely catoptric optical input system located on a path of an incoming light beam and mounted for rotation about a lateral axis on an internal elevation equipment which is angularly steerable relative to an external equipment about an internal elevation axis that is orthogonal to the lateral axis, said external equipment being angularly steerable with respect to a support about an external elevation axis aligned with the internal elevation axis and about a circular axis;

a sight stabilization mirror operatively associated with said optical input system for rotation therewith with a reduction ratio of 1/2; and

a servo-control system including;

a gyroscopic sensor tied to said block, said sensor having sensing axes parallel one with the lateral axis and the other with the internal elevation axis,

control loops for controlling motors providing actuation of the block about the lateral axis and of the internal elevation equipment about the internal elevation axis responsive to output signals from the gyroscopic sensor, and

loops for controlling motors for actuation of the external equipment about the external elevation axis and about the circular axis for the external equipment to recopy a position of the optical block,

said optical input system giving the incoming beam a size on the sight stabilization mirror that is smaller than a size of an inlet pupil of the optical input system.

9. A stabilized sighting system according to claim 8, wherein said block is steerable over an angular range of about plus and minus 10°

from a mid position.

10. A stabilized sighting system according to claim 8, further having an external assembly which is steerable about said support around said circular axis which has a direction parallel to a direction of the lateral axis in a nominal position of the system, said external equipment being steerable about said external elevation axis relative to said external assembly.

11. A system according to claim 10, wherein the external elevation equipment has a cover in the form of a ball fitted with a porthole in the form of a spherical or plane plate having faces that are parallel.

12. A system according to claim 11, wherein the external elevation equipment is mounted on ball bearings defining the external elevation axis, carried by two side plates constituting a bottom portion of the external assembly.