FR3114921A1 - DEVICE FOR POSITIONING AN ANTENNA - Google Patents

Abstract

The invention relates to a device for positioning an antenna (100) comprising an antenna positioner (200) of the elevation on azimuth type, a base (400) and an intermediate piece (300) between the base (400) and the antenna positioner (200). The intermediate piece (300) comprises a plane support surface (301) inclined. Figure for abstract: Fig. 1

Description

Device for positioning an antenna

The present invention relates to the field of satellite communications, more generally known under the name SATCOM or “Satellite Communications” in English. It relates more particularly to a device comprising an antenna positioner to allow communication with a satellite, this positioner being in particular intended to be placed on a moving carrier. By "carrier" is meant any type of vehicle used for civil and/or military applications, for example an aircraft, a land vehicle or a ship.

There are currently different types of parabolic antenna positioners to enable communication with a satellite, these positioners being either fixed relative to the ground or mobile when placed on moving carriers.

Application WO 2009/033085 describes for example a positioner of the elevation on azimuth type. This positioner has two axes of rotation, one allowing the azimuth of the parabolic antenna to be varied, that is to say the horizontal angle between the direction of the parabolic antenna and a reference direction generally corresponding to geographic north, and the other to vary the elevation of the parabolic antenna, that is to say the vertical angle between the direction of the parabolic antenna and the reference direction (geographic north). However, such positioners have the disadvantage of presenting a singular point (or “keyhole” in English) vertically, that is to say at the zenith. The concept of singular point, well known to those skilled in the art, designates a point where communication between the satellite and the parabolic antenna is difficult, or even impossible, due to the dynamic positioning constraints of the parabolic antenna in the direction said singular point in the case where the wearer is moving. In the particular case of a positioner of the Elevation on Azimuth type, the Azimuth rotation of the parabolic antenna reaches very high rotation speeds, even infinite, when passing close to the singular point vertically, so that the antenna has difficulty aligning itself with a vertically located satellite. This communication constraint is problematic if the positioner is on a moving carrier due to the dynamics that the movement of the carrier brings to the parabolic antenna. Also, it is difficult to use such positioners on moving vehicles moving in terrestrial areas where the satellites are located vertically to the parabolic antennas, in particular in the equatorial areas.

Document CA 1 236 211 describes another type of parabolic antenna positioner comprising three axes of rotation to allow the parabolic antenna to be oriented in all possible directions towards the satellite. Such a positioner does not present any singular point but proves to be very complex to produce, very cumbersome and very expensive. In addition, the addition of a third axis increases the overall overhang of the antenna positioner. This is all the more true when the antenna positioner has a low profile in order to minimize aircraft drag. Finally, this type of positioner presents low resonances which affect the steering and the performance of the pointing of the antenna vis-à-vis the satellite.

There is therefore a need to propose a solution for the positioning of an antenna which avoids presenting a singular point and which is simple and practical to implement.

The present invention aims to at least partially remedy this need.

More particularly, the present invention aims to improve the pointing of an antenna with respect to a satellite.

A first object of the invention relates to a device for positioning an antenna, said device comprising an antenna positioner of the elevation on azimuth type suitable for moving said antenna along two axes, a base intended to be fixed on a carrier, said device having a reference direction perpendicular to said base. The device further comprises an intermediate part between the base and the antenna positioner, said intermediate part comprising a flat support surface intended to receive said antenna positioner, the flat support surface being inclined so that a direction normal to said planar support surface is offset by an angle of inclination relative to the reference direction, said angle of inclination being greater than or equal to 3 degrees and less than or equal to 15 degrees.

The inclined intermediate piece allows the addition of a “tilted” axis of rotation, i.e. inclined by a few degrees. It is then possible to move the singular point out of the field of use of the antenna positioner. This increases the overall tracking capabilities of the device for positioning the antenna while maintaining a simplified mechanical design.

In a particular embodiment, the angle of inclination is greater than or equal to 5 degrees and less than or equal to 10 degrees.

In a particular embodiment, the angle of inclination is equal to 7 degrees.

In a particular embodiment, the intermediate piece comprises a circular base and a plurality of blocks extending over said circular base, said blocks forming a discontinuous bearing surface.

The realization of the support surface by a succession of independent blocks makes it possible to optimize the use of material. The overall weight of the intermediate piece in the device for positioning the antenna is thus reduced. The support surface is large enough and the blocks are rigid enough to support the load of the antenna positioner.

In a particular embodiment, the intermediate piece is movable relative to the base around the reference direction.

Thus, it is possible to shift the singular point over several azimuth positions.

In a particular embodiment, the intermediate piece is movable over 360 degrees around the reference direction.

Thus, it is possible to shift the singular point on all the azimuths.

In a particular embodiment, the intermediate part is mobile at a continuous speed.

In a particular embodiment, the intermediate part is driven by an electric motor.

In a particular embodiment, the device comprises at least one ball bearing arranged between the intermediate piece and the base.

This facilitates the movement of the intermediate piece relative to the base when shifting the singular point.

In a particular embodiment, the antenna used is a parabolic antenna or a planar antenna.

In a particular embodiment, the antenna used is an active antenna or a passive antenna.

The present invention will be better understood on reading the detailed description of embodiments taken by way of non-limiting examples and illustrated by the appended drawings in which:

there is an overall schematic view of a device for positioning an antenna according to the invention;

there is a perspective view of part of the device of the ;

there is an exploded view of the device portion of the ;

there is a perspective view of an intermediate piece of Figures 2 and 3;

there is a side view of the intermediate part of the ;

there is a partial sectional view according to section AA of the .

The invention is not limited to the embodiments and variants presented and other embodiments and variants will appear clearly to those skilled in the art.

In the various figures, identical or similar elements bear the same references.

There is a schematic perspective view of a device 10 for positioning an antenna 100 according to the invention. Such a device includes:
- an antenna positioner 200;
- an intermediate piece 300;
- a 400 plinth.

The antenna 100 is adapted to receive waves emitted by one or more satellites. In a particular embodiment, the antenna 100 is a parabolic antenna comprising a parabolic reflector and a source located at the focus of the parabola. The parabolic reflector is adapted to concentrate the waves received towards the source of the antenna which will then process them. It will now be noted that the antenna can be an active or passive device, parabolic or flat.

The antenna positioner 200 is suitable for positioning the antenna 100 relative to the targeted satellite. This antenna positioner 200 is here an elevation on azimuth type positioner able to move the antenna 100 along two axes. The antenna positioner 200 can thus rotate around a normal direction Z to modify the azimuth of the antenna. This positioner 200 can also rotate around a direction Y perpendicular to the normal direction Z to modify the elevation of said antenna. For example, it is possible to use an aeronautical low profile positioner as antenna positioner 200.

The intermediate part 300 is adapted to receive the antenna positioner 200. More particularly, the intermediate part 300 comprises a flat support surface 301 on which this positioner 200 will rest. The flat support surface 301 is inclined here. The direction perpendicular to this bearing surface is the Z normal direction around which the elevation of the antenna can be changed. The azimuth is adapted to rotate around this Z normal direction.

Finally, the base 400 is intended to be fixed on a carrier, for example an aircraft. This base 400 comprises a flat surface 401 on which the intermediate part 300 will rest. The base 400 makes it possible to define a reference direction Z' perpendicular to the flat surface 401.

The normal direction Z is shifted here by an angle of inclination α with respect to the reference direction Z'. This angle of inclination α makes it possible to obtain the offset necessary to move the singular point out of the field of use of the positioner 200. In the embodiment of FIGS. 1 to 6, the angle of inclination α is greater than or equal at 3 degrees and less than or equal to 15 degrees.

Preferably, the angle of inclination α is greater than or equal to 5 degrees and less than or equal to 10 degrees.

Preferably, the angle of inclination α is equal to 7 degrees.

Figures 2 and 3 illustrate in perspective part of the device of Figure 10. In these figures, one can thus more particularly distinguish the intermediate part 300, the base 400 as well as connection devices 500.

The intermediate piece 300 includes:
- a circular base 310 with a central opening 311;
- a plurality of blocks 320A, 320B, 320C, 320D, 320E, each block respectively having an upper surface 330A, 330B, 330C, 330D, 330E;
- a cable support 340;
- a plurality of polarizers 350, 351, 352, 353, 354, 355, 356, 357;
- a tubular part 360.

The circular base 310 forms a flat surface on which five blocks are positioned: a first block 320A, a second block 320B, a third block 320C, a fourth block 320D and a fifth block 320E. The blocks 320A, 320B, 320C, 320D, 320E are on the periphery of the circular base 310. Each block 320A, 320B, 320C, 320D, 320E generally has the shape of a rectangular parallelepiped which extends according to a predetermined curvature around of the central opening 311. More particularly, each block 320A, 320B, 320C, 320D, 320E has an upper surface 330A, 330B, 330C, 330D, 330E, two elongated side surfaces 331A, 332A, 331B, 332B, 331C, 332C , 331D, 332D, 331E, 332E and two corners 333A, 334A, 333B, 334B, 333C, 334C, 333D, 334D, 333E, 334E. The elongated surfaces 331A, 332A, 331B, 332B, 331C, 332C, 331D, 332D, 331E, 332E connect, for each block 320A, 320B, 320C, 320D, 320E, the circular base 310 to the associated upper surfaces 330A, 330B, 330C , 330D, 330E. These elongated side surfaces 331A, 332A, 331B, 332B, 331C, 332C, 331D, 332D, 331E, 332E have a curved shape which is concentric with the circular base 310. The corners 333A, 334A, 333B, 334B, 333C, 334C, 333D, 334D, 333E, 334E form the ends of the various blocks 320A, 320B, 320C, 320D, 320E. The third block 320C and the fourth block 320D respectively have a straight corner 334C, 334D. These rectilinear corners 334C, 334D are adapted to be in contact with the cable support 340. The other corners 333A, 334A, 333B, 334B, 333C, 333D, 333E, 334E of the various blocks have a rounded shape.

The various blocks 320A, 320B, 320C, 320D, 320E each have a variable height along the associated elongated side surfaces 331A, 332A, 331B, 332B, 331C, 332C, 331D, 332D, 331E, 332E. Thus, for the first block 320A, the height of the corner 334A is greater than the height of the corner 333A. For the second block 320B, the height of the corner 334B is greater than the height of the corner 333B. For the third block 320C, the height of the corner 334C is greater than the height of the corner 333C. For the fourth block 320D, the height of the corner 334D is greater than the height of the corner 333D. Finally, for the fifth block 320E, the height of the corner 334E is greater than the height of the corner 333E. By this height variation in the different blocks 320A, 320B, 320C, 320D, 320E, the associated upper surfaces 330A, 330B, 330C, 330D, 330E are inclined. In the world of embodiment of Figures 2 to 6, the change in height in each of the blocks 320A, 320B, 320C, 320D, 320E is continuously variable so that the inclination of the upper surfaces 330A, 330B, 330C, 330D, 330E is also continues. Furthermore, the variation in height in the blocks 320A, 320B, 320C, 320D, 320E, and therefore the inclination of the upper surfaces 330A, 330B, 330C, 330D, 330E, is coordinated between the different blocks so that it is possible to determine a theoretical flat bearing surface 301 passing through the various upper surfaces 330A, 330B, 330C, 330D, 330E, as illustrated in the . Thus, in the orthonormal frame X', Y', Z', of this , the theoretical planar support surface 301 has a non-zero angle of inclination α. This angle of inclination α is, in absolute value, greater than or equal to 3 degrees and less than or equal to 15 degrees. Preferably, the angle of inclination α is, in absolute value, greater than or equal to 5 degrees and less than or equal to 10 degrees. Preferably, the angle of inclination α is, in absolute value, equal to 7 degrees.

It will be noted that the blocks 320A, 320B, 320C, 320D, 320E have different lengths. By "block length" is meant the curvilinear distance between two corners of the block. Thus, the first block 320A has a shorter length than the second block 320B. The second block 320B has a shorter length than the third block 320C. Similarly, the third block 320C has a shorter length than the fourth block 320D. It is the fifth block 330E which extends over a larger area of the circular base 310.

It will also be noted that the blocks 320A, 320B, 320C, 320D, 320E have an identical width. By "block width" is meant the distance between two elongated side surfaces of the block.

The intermediate part 300 also comprises a plurality of polarizers 350, 351, 352, 353, 354, 355, 356, 357 intended to facilitate the installation of the antenna positioner 200 on the intermediate part 300. This plurality of polarizers thus comprises pawns 350, 354 protruding respectively relative to the circular base 310 and relative to the upper surface 330D of the fourth block 320D. The polarizers also include holes 351, 352, 353, 355, 356, 357 extending respectively in the depth of the first block 320A for the hole 351, in the depth of the second block 320B for the hole 352, in the depth of the third block 320C for the hole 353, in the depth of the fourth block 320D for the hole 355 and in the depth of the fifth block 320E for the holes 356 and 357. flat support surface 301. It will be noted that the antenna positioner 200 also comprises additional means (not shown) to the polarizers 350, 351, 352, 353, 354, 355, 356, 357 of the intermediate piece 300.

The intermediate piece 300 further comprises a tubular part 360 which extends under the circular base 310. This tubular part 360 is connected to the circular base 310 via the central opening 311. Thus, it is possible to set up the different connecting devices 500. These connecting devices 500 include:
- a slip ring 510;
- fixing fittings 520, 521, 522;
- cables 530, 531, 532.

The slip ring 510 comprises a main body 511, two fixing end pieces 512, 513 and a cap 514. The main body 511 is adapted to rotate inside the central opening 311 of the intermediate piece 300. The cap 514 is suitable for protecting the 510 slip ring against the infiltration of dust or projections. The fixing end pieces 512 and 513 are adapted to receive a first cable 530 and a second cable 531. This first cable 530 is for example a coaxial cable (RF). The second cable is an antenna power supply cable 100. The connection device 500 also includes a third cable 532 adapted for the transmission of digital information. These three cables 530, 531, 532 are fixed to the cable support 340 of the intermediate piece 300 via the fixing fittings 520, 521, 522.

The tubular part 360 is adapted to be housed in a ball bearing 600. The ball bearing 600 comprises:
- a moving part 610;
- A fixed part 611;
- a plurality of balls 612.

The mobile part 610 is mechanically linked to the tubular part 360 of the intermediate part 300. The fixed part 611 is mechanically linked to the base 400. The tubular part 360 is therefore mobile in rotation relative to the base 400 via the plurality of balls 612. A sealing flange 700 is adapted to cover the ball bearing 600. The ball bearing 600 allows the intermediate piece 300 to be movable relative to the base 400 around the reference direction Z'. In the configuration of FIGS. 2 to 6, the intermediate piece 300 is movable over 360 degrees around the reference direction Z. In a particular embodiment, the ball bearing has great stiffness to limit vibrations. It will also be noted that a position encoder 710 is arranged between the intermediate part 300 and the base 400. This position encoder 710 is adapted to give the position of said intermediate part 300 with respect to this base 400.

The intermediate part 300, the ball bearing 600, the sealing flange 700 come to rest on a reception zone 410 of the base 400. This reception zone 410 is in the form of a portion of tube protruding with respect to the flat surface 401 of the base 400. The shape of this tube portion is adapted to the intermediate part 300, to the ball bearing 600 and to the sealing flange. The base 400 also includes a box 420 extending the reception area 410. The box 420 includes a cover 421 and a bottom 422. The cover 421 and the bottom 422 are adapted to cover a printed circuit board 430. This printed circuit board 430 comprises a plurality of electronic components 431 in order to control the operation of the antenna 100. It will be noted that the cover 421 has a plurality of fins 423 to facilitate the evacuation of the heat produced by the printed circuit board, outside of the box 420.

There is a partial sectional view according to section AA of the . In this sectional view, the rotor 800 of an electric motor can be seen. This rotor 800 is adapted to drive the intermediate part 300 via the tubular part 360. In a particular embodiment, this electric motor drives the intermediate part 300 according to a continuous speed. As already described, the tubular part 360 rotates relative to the base 400 via the ball bearing 600.

Thus the invention makes it possible to improve the pointing of an antenna with respect to a satellite by moving the singular point out of the field of use of the antenna positioner 200.

It also brings the following advantages:
- the ability to perform satellite tracking is increased;
- the capacity requirement of the electric motor is reduced;
- the motorization of the antenna positioner ensuring the azimuthing is less stressed at high elevation;
- the vibrations of the device for positioning the antenna are controllable compared to a conventional 3-axis solution;
- The intermediate piece 300 compensates for changes in aircraft heading;
- a good positioning of the intermediate part 300 makes it possible to orient the antenna in the plane of the satellite which makes it possible to optimize the orientation of the antenna with respect to the plane of the equatorial on which the targeted satellite is located as well than its neighbours. This is particularly true for antennas of rectangular shape, especially at low elevation;
- the power of the antenna 100 can be increased which improves the Equivalent Isotropic Radiated Power (EIRP) also called EIRP in English for “Effective Isotropic Radiated Power”.

The invention is not limited to the embodiments and variants presented and other embodiments and variants will appear clearly to those skilled in the art.

Thus, the positioning device is suitable for positioning any type of antenna that can be used on a carrier, such as a planar antenna, an active antenna or a passive antenna.

In the embodiment of Figures 2 to 6, the intermediate piece 300 is in a single part. Alternatively, the intermediate piece 300 is an assembly of different elements. Thus, the blocks can be added elements fixed to the circular base, for example by gluing, screwing or any other means.

Thus, the connection devices 500 may not include slip rings.

Claims (11)

Device for positioning an antenna (100), said device (10) comprising:
- an antenna positioner (200) of the elevation on azimuth type suitable for moving said antenna (100) along two axes;
- a base (400) intended to be fixed on a carrier, said device (10) having a reference direction (Z') perpendicular to said base (400) characterized in that the device (10) comprises:
- an intermediate piece (300) arranged between the base (400) and the antenna positioner (200), said intermediate piece (300) comprising a flat bearing surface (301) intended to receive said antenna positioner (200 ), the planar support surface (301) being inclined so that a direction (Z) normal to said planar support surface (301) is offset by an angle of inclination (α) with respect to the direction reference (Z'), said angle of inclination (α) being greater than or equal to 3 degrees and less than or equal to 15 degrees. Device for positioning an antenna (100) according to claim 1, in which the angle of inclination (α) is greater than or equal to 5 degrees and less than or equal to 10 degrees. Device for positioning an antenna (100) according to any one of claims 1 or 2, in which the angle of inclination (α) is equal to 7 degrees. Device for positioning an antenna (100) according to any one of claims 1 to 3, in which the intermediate part (300) comprises a circular base (310) and a plurality of blocks (320A, 320B, 320C, 320D , 320E) extending over said circular base (310), said blocks (320A, 320B, 320C, 320D, 320E) forming a discontinuous bearing surface (330A, 330B, 330C, 330D, 330E). Device for positioning an antenna (100) according to any one of Claims 1 to 4, in which the intermediate part (300) is movable with respect to the base (400) around the reference direction (Z'). Device for positioning an antenna (100) according to claim 5, in which the intermediate part (300) is movable over 360 degrees around the reference direction (Z'). Device for positioning an antenna (100) according to any one of claims 5 or 6, in which the intermediate part (300) is movable at a continuous speed. Device for positioning an antenna (100) according to any one of Claims 5 to 7, in which the intermediate piece (300) is driven by an electric motor (800). Device for positioning an antenna (100) according to any one of Claims 5 to 8, in which the said device (10) comprises at least one ball bearing arranged between the intermediate piece (300) and the base (400) . A device for positioning an antenna (100) according to any one of claims 1 to 9, wherein said antenna (100) is a parabolic antenna or a planar antenna. A device for positioning an antenna (100) according to any one of claims 1 to 10, wherein said antenna (100) is an active antenna or a passive antenna.